sem 2 exam Flashcards

Question

facilitated diffusion

Answer 1

diffusion with help, where molecules diffuse across cell membrane with assistance of carrier proteins. carrier protein changes shape and molecule is released on the other side of membrane diffusion takes place from high concentration to low concentration does not require ATP for example amino acids or glucose proteins bind to molecules bring in glucose and AA

Answer 2

process of using ATP to pump molecules across membrane against the concentration gradient they move from low concentration to high concentration using active transport a cell can take in or pass out substances regardless of their concentration which is why energy is needed. For example membrane pumps sodium ions and potassium ions which are high in the nerve cells of the body bring in glucose, certain ions, AA

Answer 3

process that brings materials into the cell involves the cell absorbing large particles such as proteins or even whole organisms such as bacteria, viruses, from outside by engulfing them with the cell membrane to form a vesicle like a bubble with in the cytosol brings in cholesterol, iron ions The cell membrane folds around a particle until the particle is completely enclosed, the vesicles so formed then pinches off and suspended in the cells cytoplasm

Answer 4

release of molecules from the cell, things leaving the cell contents of vesicle are emptied, vesicle formed inside cell then, membrane of vesicle fuses with the cell membrane and contents emptied into extracelluar fluid empty secretions such as mucus or digestive juices

Answer 5

covering and lining tissue that protects lines inside of organs consist of cells very closely joined together cells that vary in size in different tissues (thin&flat, column/cube shaped) mouth lining, outside lung, outer layer of skin

Answer 6

supporting tissue that holds body parts together made of widely spaced cells separated by noncellular material called matrix eg: blood, bone, adipose (fat) tissue, ligaments (bone to bone), tendon (muscle to bone), cartilage under skin there is loose connective tissue matrix of blood is plasma

Answer 7

contracting tissue that responds to stimulus made of long, thin, muscle cells/fibres responds to stimulus by contacting and relaxing skeletal: (striated/voluntary) attached to bones arms and legs smooth: (non striated/involuntary) in walls of many organ uterus, stomach, blood vessels cardiac: branched and striated with intercalated discs/involuntary) contacts to pump blood around body involuntary: something you can't control

Answer 8

carries message in form of electrical impulses around body found in brain, spinal cord, nerves composed of neurons (nerve cells) with long projections from the cell body stimulation of a neuron causes messages of to be passed along projections throughout the body

Answer 9

total of all chemical reactions/processes occurring in your body. maintains a balance between energy released and energy used c:breaking down large molecules broken down to smaller ones energy released cellular respiration a: building up small molecules built up to larger ones energy required

Answer 10

proteins that allow chemical reactions to take place at body temperature enzymes work by reducing activation energy enzymes are specific: enzyme and its substrate have a shape and structure that allow them to fit together. complementary part of enzyme where molecule combines with substrate is the active site, when combined it is the enzyme-substrate complex 5. enzymes can be denatured (lose shape) by heat and lose catalytic properties 6. optimum temp is 37ºC and pH varies. over 45ºC enzymes are denatured

Answer 11

1. increasing concentration of enzyme can increase rate 2. increasing substrate concentration will increase rate as more molecules contact enzymes 3. products must be removed continuously 4. has optimum temp 5. has optimum ph 6. some need cofactors/coenzymes to change active site shape for reaction 7. enzyme inhibitors slow or stop enzyme activity. controls reactions

Answer 12

60% heat energy 40% for ATP inorganic phosphate group joins ADP, ADP and phosphate have a weak bond with stored energy, removing phosphate group releases energy ATP can transfer energy from cellular respiration to cell processes that use energy and ADP can be reused

Answer 13

glycolysis: breaks down one glucose molecule to make 2 two molecules of pyruvate (pyruc=vic acid C3H4O3) also makes 2 molecules of ATP occurs in cytoplasm of cell, doesn't require oxygen If no oxygen is present, pyruciv acid goes to lactic acid lactic acid goes to liver nd recombines with oxygen to make glucose

Answer 14

Krebs cycle= citric acid cycle series of reactions where pyruvate is completely broken down to CO2. Krebs cycle make 2 ATP, electron transfer makes 34 ATP in mitochondria, requires oxygen

Answer 15

during high intensity exercise, O2 can't be supplied fast enough, so muscles burn glucose anaerobically, producing lactic acid lactic acid build up in muscle is toxic and causes fatigue and pain lactic acid is taken by the blood to the liver where it is recombined to form glucose then glycogen (storage form of glucose) after exercise breathing is heavy so oxygen can be repaid recovery oxygen: oxygen required after exercise

Answer 16

1. transport nutrients and oxygen to cell 2. transport co2 and wastes away from cell 3. transport hormones to cells 4. regulate pH 5. thermoregulation 6. protect against disease (WBC)🦠 7. clotting to prevent blood loss 8. maintain water and ion content in bodily fluids 💦

Answer 17

liquid: plasma 55% | non-liquid: formed elements 45% (cells and cell fragments)

Answer 18

RBC suited for o2 and co2 transport have HGB (protein) and has no nucleus to make room for it ( when combine with o2, HGB is red) large SA to V to speed up gas exchange made in bone marrow, destroyed in liver/spleen by macrophages (120 days)😩 small, 8um and flexible to go through narrow capillaries 1. contain Hgb which combines with oxygen 2. have no nucleus, more room Hgb 3. biconcave disc shape: increases surface area for gas exchange and thicker edges= large volume for HGB

Answer 19

fight infections/provide immune responses granulocytes: granular cytoplasm, lobed nucleus agranular: lymphocytes and monocytes macrophage is type of monocyte- phagocytic few minutes to YEARS!! get rid of dead or injured cells 😭(RIP) and invading microorganisms 🦠

Answer 20

small cell fragments with no nucleus😔 1/3 of RBC🖕👌 made in bone marrow life span of a week important in coagulation

Answer 21

91% water rest is dissolved substances glucose, AA, ions, wastes (urea: waste of protein metabolism), gases

Answer 22

3% dissolved in plasma 97% carried in HGB to make oxyhemoglobin this bond is v loose to breaks down easily to release oxygen when o2 conc is high (capillaries in lungs), o2 combines with HGB easily when o2 conc is low (cells) oxyhemoglobin breaks down

Answer 23

8% dissolved in blood plasma 22% combines with HGB to form carbaminohaemoglobin 70% carried in plasma as bicarbonate ions (HCO3-) (H+) co2 diffuse into plasma because of con grad, most of it reacts with water to from carbonic acid. this then dissociates into hydrogen ions and bicarbonate ions in lungs: 8% diffuses out 22% breakdown then diffuse 70% ions recombine to carbonic acid then breaks down by enzymes to water and co2, then diffusion

Answer 24

carry blood away from the heart carry oxygenated blood have thick, smooth, muscular walls with elastic fibres no valves high pressure blood because it is closer the heart, increase as ventricles contact further down in skin because it contains high pressure blood

Answer 25

carry blood toward the heart carry deoxygenated blood thin, relatively inelastic (pressure is constant) walls with little muscle have valves blood is under low pressure because most of the pressure is lost as it flows through the tiny capillaries no elasticity

Answer 26

Microscopic connects veins and arteries network 1 cell thick: thin for easy diffusion of nutrients and wastes

Answer 27

walls are made of smooth muscle and elastic fibres (stretch and recoil). the recoil keeps blood moving and maintains pressure Vasoconstriction: contraction to reduce the lumen (inside space) size/diameter of artery to reduce blood flow to an area. reduce loss of body heat in cold temperatures, arteries constrict to let less blood go to the skin and more in the core region. vasodilation: relaxing to increase lumen size, increase blood flow to an organ.In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation . This allows more heat to be lost from the blood. adrenaline causes vasoconstriction in most arterioles, but vasodilation in skeletal/cardiac muscle

Answer 28

systole: when heart muscles contract, pumping diastole: when heart muscles relax, filling artrial systole/ventricular diastole: atria contracts forcing blood into ventricles ventricular systole/ atrial dyastole: atria relax and refill while ventricles contact which forces blood into arteries

Answer 29

=stroke volume x heart beat stoke volume= volume of blood forced from a ventricle each contraction cardiac output= amount of blood leaving leaving a ventricle every minute

Answer 30

collection of nerve cells in the wall of the right atrium pacemaker starts each cardiac cycle by sending nervous impulses which cause the atria walls to contracts, nerve impulses reach the atrioventricular node causing ventricles to contract-> frequency of this is called heart rate

Answer 31

when you exercise, large increase in blood flow Is needed to supply oxygen and nutrients and remove carbon dioxide and heat vasodilation of blood vessels in muscles and contraction to blood vessels started by anticipatory response from nervous system continued because wastes (CO2, lactic acid, heat) all act as vasodilators

Answer 32

protein molecules of the surface of erythrocytes that determine blood type capable of stimulating formation of antibodies antibodies: molecules in plasm that remove foreign bodies (pathogens) leucocytes then engulf and destroy inactivated pathogens specific to each pathogen

Answer 33

a further antigen on erythrocyte surface rh- doesn't have antigen and makes antibodies that destroy the Rhesus factor rh+ person has the antigen that makes no antibodies that destroy the Rhesus factor antibody for rh is not normally present in plasma only produced after exposure to it. 1st exposure sensitises person, so nay subsequent exposure leads to rapid production of antibodies

Answer 34

``` antibodies in plasma combine with antigens on the surface of foreign blood Agglutination occurs (clumping of cells) ```

Answer 35

whole blood: blood taken with anti-clotting agent added (eliminates disease risk) Autologous: patienst own blood used that was collected before surgery red cell concentrate: blood centrifuged and only erythrocytes taken (anaemic/heart disease) plamsa: used to provide extra clotting factors in severe bleeding and liver disease platelets: when platelets are too low Cryoprecipitate: plasma frozen and slowly thawed. contains many clotting factors and used for haemophiliacs Immunoglobulins: group of proteins acting as antibodies extracted from blood of people that are immune to a particular disease.

Answer 36

1. injury to lining of a blood vessels exposes a rough surface to which plackets stick to 2. sticking platelet attract others, so a plug is built at the site of the injury 3. platelets release vasoconstricttors that enhance constriction of damaged vessels ^for small injuries 4. blood clotting factors form a fibrin cloth reinforces the seal. fibrin cloth form a mesh that traps blood cells after clot is formed, clot retraction occurs(threads contract, pulling damaged blood vessel edges together,) as this occurs a fluid called serum is squeezed out. then scab formed-->acts as a mechanical barrier to the entry of pathogens. blood coagulates to prevent blood loss from injured tissue. clotting factors catalyse the conversion of plasma protein to an active enzyme

Answer 37

nasal cavity with l&r chamber (nostrils) that lead to pharynx projections known as conchae increase surface area filters (hair), warms (capillaries), moistens (mucus) the air before it enters the lungs has olfactory receptors enhances sound produced in speech mucus and hair trap dust

Answer 38

air from nasal cavity passes through here 13cm, direct air to larynx used to pass food to oesophagus

Answer 39

stretched between cartilage are two folds of mucus membrane called vocal folds the edges have elastic ligaments that vibrate (vocal chords)

Answer 40

has c-shaped cartilage bands that allowing the oesophagus to expand into the gaps in the trachea when swallowing lined with ciliated mucus membrane to trap solid particles mucus is produced from goblet cells

Answer 41

where trachea divides into secondary and tertiary bronchi | kept open with cartilage and lined with cilia and mucus

Answer 42

very fine tube that lead to the alveoli | walls of smooth muscle, no cartilage

Answer 43

around 300 million each lung tiny air sacs, in clusters, wall have very thin membrane for diffusion 1 cell thick, large sa surrounded by dense network of capillaries chemical surfactant coats the inside alveoli to lubricate it and prevent friction and closing of alveoli

Answer 44

right has 3 lobe left has 2 lobe pleura membrane covers surface of lungs and inside of chest. between 2 layers of membrane is pleural fluid which hold lung against inside of chest wall and allows lungs to slide along wall when breathing

Answer 45

muscles between ribs, internal and external when the external muscles contract they they pull the ribs upwards and outwards, increasing volume of thoracic cavity contraction of the internal muscles pulls ribs closer, decreasing the thoracic cavity. this increase pressure inside lungs and air is diffused out

Answer 46

dome shaped muscle | contraction increases volume of thoracic cavity

Answer 47

1. alveoli give lungs a very large internal surface area, so lots of gas can be exchanged in a short amount of time 2. each alveoli is well supplied with blood vessels, so that as much blood as possible is close to the air in the alveolus. the continuous flow of blood helps maintain a difference in concentration of o2 and co2 in blood and lungs. concentration gradient is necessary for diffusion 3. wall of alveolus is very thin (1 cell thick), gas doesn't have to travel far when moving in and out of blood. 4. lungs positioned deep inside body to prevent excessive evaporation of fluid that covers the respiratory surfaces, it is important that the alveolus membrane is covered by a thin layer of moisture because gases can only diffuse in and out of the blood when they are dissolved in fluid. 5. the lung volume can be changed by movements of the respiratory muscles, so that the air is made to move in and out of lungs. constant changing of air in the alveoli helps to ensure that there s always a difference in o2 and co2 concentration in the lungs and blood.

Answer 48

blood in capillaries is from the pulmonary arteries. this blood has low level of oxygen, lower than the concentration of oxygen in the alveolus. oxygen dissolves in the moisture on the inside of the alveoli and diffuses through the membrane through capillary walls and into blood. the blood arriving at alveoli has high concentration of co2. (waste from cells) so the concentration of co2 in capillaries is higher than the concentration in the alveolus. co2 diffuse out of blood and into the alveolus. this is why the expired air has more co2

Answer 49

constant flow of blood through capillaries.the new blood pumped is low in o2 and high in co2 so conc grad is maintained constant movement of air in and out of lungs. the air is high in o2 and low in co2

Answer 50

pressure in lung must be less than atmospheric pressure, this is done by increasing lung volume diaphragm and external intercostal muscles contract diaphragm flattens and EIM contraction causes ribcage to move up and out as pleura sticks to internal wall of chest cavity the lungs expand with it air flows in til pressure is equal

Answer 51

diaphragm and external intercostal relaxes diaphragm bulges more into chest cavity and ribcage moves down reduces thoracic cavity air flows out til equal forced breathing: intercostal muscles contract to actively lower ribcage

Answer 52

mechanical: jaw and teeth cut, tear, crush and grind food tongue mixes it up with mucus into a round lump called bolus chemical: salivary amylase ptyalin begins starch breakdown large starch molecules to smaller ones

Answer 53

3 types, 2 of each 1. parotid salivary gained (front of ear) 2. sublingual salivary gland (under the tongue) 3. sub mandibular salivary gland (under mandible bone)

Answer 54

incisors: (4) biting and cutting, chisel shaped canines: (2) tearing, pointy edge premolars: (4) crushing and grinding molars: (6) crushing and grinding 32 together

Answer 55

bolus is pushed into pharynx by tongue oesophagus: made of mucosa, muscle (circular and longitudinal) oesophagus pushes food from the mouth to the stomach by a wave of circular, muscular contractions called PERISTALSIS. movement lubricated by mucosa, prevents friction

Answer 56

after passing the diaphragm, the oesophagus reaches the stomach mechanical: waves of muscular contraction churns food and mixes it with gastric juices (HCl and enzymes) into thick soupy liquid called chyme stomach has third muscle (oblique) to assist with churning chemical: gastric juices made in gastric glands of mucosa, contains enzyme pepsin (gastric protease) that begins protein breakdown. pepsin works in acidic conditions, that's why it need activated by Hal to go from pepsinogen to pepsin absorption: only alcohol and drugs absorbed in to blood

Answer 57

deep folds called rugae line stomach to help it expand to increase volume first is the cardiac sphincter then it is the pyloric sphincter thick mucus walls

Answer 58

chyme goes into the duodenum (1st part of small intestine), through the pyloric sphincter (prevents food spilling into the duodenum too soon) transferred by peristalsis (2-8hrs)

Answer 59

1. duodenum 2. jejunum 3. ileum

Answer 60

mechanical: waves of muscular contractions (L&C walls of small intestine),churn the food, peristalsis bile stored in gall bladder, and made in liver, is secreted through duct and emulsifies fats chemical: pancreatic juices from the pancreas enter the duodenum (pH8) and neutralises the chyme, contains enzymes - pancreatic protease: proteins to amino acids -pancreatic amylase: carbohydrates to simple sugars -pancreatic lipase: fats to fatty acids and glycerol intestinal juice fro intestinal glands in the mucosa completely chemical digestion

Answer 61

emulsifies fats (breaks them down to tiny droplets, doest chemically change it) has salts in it, not an enzyme travels via duct to duodenum, helps neutralise chyme increases surface area of fats so pancreatic lipase cancan quicker

Answer 62

most products of digestion (V+M, H2O) are absorbed into the blood capillaries of the villi through diffusion, osmosi and active transport (depends on conc) fast and fat soluble vitamins absorbed into the lacteals of the lymphatic system and transported to the chest, where they enter the blood and go to the liver lacteals are permeable to larger fat molecules villi and microvilli in small intesine increase surface area to increase absorption rate

Answer 63

very long (6m) inner mucosa lining has many folds mucosa has villi on it, cells covering villi have further projections (microvilli) has dense network of capillaries to absorb nutrients epithelium is very thin (1 cell thick)

Answer 64

waste products of digestion go through large intestine 1.5 m long, no villi but mucosa is secreted to lubricate bacteria breakdown remaining organic compounds vitamins, minerals and water absorbed into blood, leaving contents semi-solid faeces stored in rectum and eliminated through anus faeces consists of, undigested cellulose, bacteria, bile, pigments, cells. FUN FACT: cellulose stimulates movements of the alimentary canal.

Answer 65

``` caecum (appendix is attached) appendix (lymphatic tissue) ascending colon, transverse colon, descending colon sigmoid colon rectum anus ```

Answer 66

fatty acids + glycerol: diffusion into lacteal AA: active transport water and water soluble vitamins: diffusion simple sugars: active transport

Answer 67

at the atrial end of the blood capillary, fluid tends to leak because of high pressure, some fluid returns at the venous end of capillary, the rest of the fluid now in tissues is returned as lymph. clear watery liquid formed from interstitial fluid (between cells). help destroy dangerous bacteria 90% of this fluid goes back into the blood capillaries and the rest enters the lymphatic vessel (interstitial fluid in a lymphatic vessel is called lymph) the lymph capillaries lined with overlapping epithelial cells that allow fluid to enter. Capillaries open to large vessels, often with valves to prevent back flow

Answer 68

occur at intervals along lymphatic vessels where lymph vessels carry lymph to surrounded by capsule of connective tissue large particles are trapped in meshwork of fibres as lymph flows through spaces in lymph node lymphocytes and macrophages (phagocytosis) are produced to fight off invaders in lymph.

Answer 69

sent through the efferent vessel and sent through the right lymphatic or thoracic duct where merges with the veins and the fluid reenters the circulatory system

Answer 70

lungs: release co2 and h20 vapour from cellular respiration liver: convert substances in form we can excrete skin: sweat glands, removes waste, and sweat for cooling, salt. contains byproducts alimentary canal: passes out bile pigments from breakdown of haemoglobin to faeces kidney: principal excretory organ, filters blood stream to remove toxic waste products

Answer 71

main function is protection and temperature regulation and excretion of wastes epidermis (closely packed epithelial cells/tissues) dermis (connective tissue) has sweat glands, hair follicles, nerves and capillaries subcutaneous layer (innermost skin layer) sweat glands excrete 500ml of water a day contains salts, urea, lactic acid, drugs sweat glands are found in lower layers of skin, a duct carries sweat to a hair follicle or skin surface where it opens at a pore. cells surrounding glands contract and squeeze the sweat to the skin surface

Answer 72

if other energy sources have been used up, body can metabolise large amounts of protein. main byproduct of breaking down proteins is ammonia (NH3), excess protein in diet can't be stored deamination: removal of the amino group from excess amino acid molecules in the liver forming ammonia AA + O2 ---(enzymes)--> carbohydrate + ammomnia ammonia is toxic so they are made into urea (less toxic molecule) the carbohydrate is broken down into energy energy + CO2 + NH3 ----> UREA + H2O ammonia is converted to urea compound made by CO2 and NH3 in the liver. urea circulates in blood and is filtered out by kidneys urea is low toxicity so it needs water to dissolve it in and get rid of it (urine) worn out cells are a source of protein and are broken down into AA

Answer 73

1. deamination 2. detoxification: alcohol, drugs, antibiotics 3. hormone removal, deactivates and converts to a form to be excreted 4. dead RBC and haemoglobin are broken down in liver and passed out with faeces 5. carbohydrate metabolism: excess glucose turned to glycogen for storage and glycogen turned back to glucose when needed. depends on body needs 6. lipid metabolism: excess carbs to fat 7. heat production, main heat producing organ in body 8. production of bile: emulsifies fat in duodenum 9. stores vitamins and minerals 10. protein synthesis

Answer 74

water most abundant in body 40-80% intracellular and extracellular fluid water intake=water outputs amount of water consumed and urine formed is regulated by brain receptors and ADH hormone (antidiuretic hormone) which target nephrons and stops them from releasing water through urine ADH produced when body is dehydrated

Answer 75

renal cortex:outer position, dark red, contains bowman's capsule renal medulla: innermost region, holds renal pyramids (8-18), loop of henle, pale pink renal pelvis: inner layer, cream colour, collects urine from collecting ducts -> 3 major calyces-> renal pelvis before it goes to bladder. acts as funnel for urine flow into ureter

Answer 76

microscopic functional unit of kidney nephron = glomerular capsule + renal tubule (5cm long) + associated blood supply I million nephrons each kidney

Answer 77

1. renal corpuscle (glomerular capsule) 2. proximal convoluted tubule. descending limb of loop of henle 3. loop of henle ascending limb of loop of henle 4. distal convoluted tubule, 5. collecting ducts

Answer 78

consists of glomerulus (knot of capillaries) inside glomerular capsule (double walled cup that that surrounds glomerulus) afferent: enters, arteriole going into RC efferent: away, arteriole leaves glomerulus filtration takes place in real corpuscle

Answer 79

1. renal artery (blood from aorta) divides into afferent 2. afferent arteriole forms knot of capillaries (high bp) 3. efferent arteriole breaks up into network of capillaries called peritubular capillaries 4. peritubular capillaries surround PCT, desc and asc limb of LOH and CD 5. venule 6. renal vein to inferior vena cava things get squirted out from glomerulus to glomerular capsule

Answer 80

glomerular filtration selective reabsorption tubular secretion

Answer 81

high BP in GC is due to the afferent arteriole having a wider diameter efferent arteriole leaving glomerulus is narrower, resistance to blood flow High BP forces small ions, glucose, AA, H2O, through capillary walls and into bowman capsule space large molecules, (RBC, large proteins), remain in capillaries the filtrate is collected by Bowmans capsule and enters tubule

Answer 82

of filtrate by cells that line renal tubule (H20, salts, glucose, AA, vitamins, minerals, ions) water leaves membrane on descending part of LOH Na and Cl reabsorbed on ascending limb of LOH (so doesn't lose more water) under hormonal control of ADH where more or less water can be reabsorbed facultative reabsorption: active reabsorption of H20, ATP is needed ADH causes kidneys to retain water (alcohol interferes with this action

Answer 83

adding materials/molecules to filtrate active transport peritubular secretion into tubes of nephron, last chance for unwanted materials to leave the body remove H ion to regulate pH removes ammonium ions as well water and other substances not reabsorbed drain forms the collecting ducts into renal pelvis to ureter and bladder ADH in kidneys (CD), to remove water from urine, decrease urine output, makes urine more concentrated dark yellow instead of pale yellow

Answer 84

1. glomerular capsule surround glomerulus to collect fluid filtered out of blood capillaries 2. arteriole leading out of glomerulus is narrower, so this raises BP so more fluid is filtered out of blood 3. tubule has 2 sets of convolutions and a long loop so that each tubule has a large SA for secretion and reabsorption 4. 1 million nephrons each kidney, increase surface area for reabsorption

Answer 85

0.5 litres per day lost to remove wastes more water leads to increase urine output and decrease in concentration 99% of water reabsorbed no protein no glucose contains uric acid (breakdown of nucleic acids) and creatinine (breakdown of creatine phosphate) 96% water 2% urea 1.5% various ions 0.5% other (creatinine, uric acid)

Answer 86

``` passive: water urea glucose AA vitamins salts ```

Answer 87

passive: water ``` active: salts glucose AA vitamins Na, Cl ions ```

Answer 88

``` active: H ion NH4 ion creatinine toxins drugs (penicillin) neurotransmitters UREA water (under ADH influence) ```

Answer 89

movement postural support heat production during cold stress (shivering)

Answer 90

1. contractibility: cable of getting shorter, contracts and relaxes 2. extensibility: can be stretched 3. elasticity: when stress is removed, they return to original shape/length (recoil) 4. excitability: nerve stimulations, muscles are activated by nerve impulses from the brain

Answer 91

muscle cell is an elongated cyclinder that lie parallel to each other, many nuclei and mitochondria and has sarcolemma and sarcoplasm. made of bundles of muscle fibre held together by connective tissue. connective tissue have hundreds of myofibrils which is made of myofilaments which is made of actin and myosin

Answer 92

cell membrane around muscle cell cytoplasm of muscle cell t tubule, contains, stores, recreates Ca ion

Answer 93

small unit of skeletal muscle that contracts made of acting and myosin filaments sections/division of sarcomere: - Z lines, boundary of sarcomere. where 1 joins onto the next, anchors for actin - A band: thick filament region (dark band is myosin) - I band: point between thick filaments, so thin filaments (light band are actin) - H zone: distance between thin filaments in middle - M line: midline of sarcomere

Answer 94

head, neck, tail head: ATP binding sited actin binding site myosin heads stick out of filaments and act as cross bridges. moving myosin heads creates a power stroke resulting in muscle contraction movement is driven by ATP filaments do not move

Answer 95

2 proteins chains wrapped around each other makeup actin proteins are: - troponin: small round proteins that allow Ca ion to it. Ca ion binding site - tropomyosin: long thin strand, blocks the myosin binding site, acts as regulator actin filament and actin binding proteins regulate accessibility of the myosin heads. actin moves, not myosin

Answer 96

1. nerve impulses stimulate muscle fibres 2. ATP breakdown into ADP and phosphate group, which provides energy. binds to myosin head at binding site 3. calcium binds to troponin at binding site and moves tropomyosin out of its connection 4. myosin heads attach to actin 5. cross bridges form 6. myosin pulls actin filaments towards centre of sarcomere, movement occurs 7. actin sliding across myosin 8. sliding of filaments occurs due to continuous attaching and detaching of myosin heads on actin filaments (breaking and remaking cross bridges-like rowing) 9. results in muscles shortening, contraction filaments don't change in size

Answer 97

``` I band shortens h band shortens Z lines come closer together (shorten) sarcomere shorten by about 1/3 of its resting length a band remains the same length ```

Answer 98

skeletal muscles are never completely relaxed, in mild state of tetanus many different fires take it in turn to contract but without movement muscle tone is important when standing/sitting: stabilises skeleton and constantly adjusts to maintain posture and balance eg head is her up by partial contraction of neck muscles maintenance of muscle tone when active or at rest is complex receptor cells in muscles initiate sin voluntary nerve responses in spinal cord and brain to adjust muscle tone

Answer 99

agonist, prime mover: contracting muscle (bicep), causes desired action antagonist: relaxing muscle (tricep), have opposite reaction origin:end of muscle fixed to stationary bone insertion: attachment of the other end of muscle to movable bone origin of bicep: shoulder, scapula insertion of bicep: forearm, attached to radius origin of tricep: shoulder, scapula and humerus insertion of tricep: forearm, ulna synergists: helps an agonist or prime mover fixators: when synergist immobilises a joint, keeps joint firm and still during movement

Answer 100

renal artery to afferent arteriole to renal corpuscle to efferent arteriole to peritubular capillaries peritubular capillaries surround the proximal and distal convoluted tubules, limbs of LOH, CD venous blood drains from the network of capillaries and leave kidney in renal vein

Answer 101

held together in bundles, sheath of connective tissue surrounds each bundle so it can function as an individual unit connective tissue allows adjacent bundles to slide easily over each other as they contract sheath of connective tissue join each other and towards the end of the muscle they taper and blend CT gives muscle toughness

Answer 102

long term exposure to toxins cause damage to alveoli making them lose their elasticity reducing internal surface area loss of elasticity means that lungs are always inflated and breathing requires voluntary effort

Answer 103

development of tumour in lungs | common in bronchi walls, irritates mucous membrane causing excess mucous production which make alveoli rupture

Answer 104

Pneumonia: bacterial, fungal, viral tb: bacterial inflammation from infection causes secretion of fluid and mucus into alveoli -> reducing amount of air they have

Answer 105

allergic response to foreign substances that enter the body muscles around bronchi go into spasm causing narrowing making it hard to breathe less o2 to cells

Answer 106

when large intestine movements are reduced and contents remain their for long time. poo is harder lack of cellulose

Answer 107

frequent defection of watery faeces | irritation of both intestines, increase peristalsis so contents mover through before enough water is absorbed

Answer 108

soluble fibre intake lowers cholesterol | they trap fats in intestines and prevent their absorption into the body

Answer 109

unable to tolerate gluten if they do, immune system attack villi in small intestine, meaning nutrients not absorbed as well which could lead to malnourishment

Answer 110

solid crystals built up in kidneys, when urine urine is too concentrated and insuffienct fluids small crystals pass without too much pain large crystals get stuck in thin tubes and cause lots of pain

Answer 111

when kidneys lose ability to excrete waste and control fluid levels most affect glomeruli and decreases it ability to filter blood I-> RBC and proteins may leave blood into filtrate if too many proteins are lost there is decrease in blood protein and increase in fluid tissues leading to swelling

Answer 112

method of waste removal when kidney failure occurs

Answer 113

peritoneum:membrane lining abdominal cavities and organs, has a rich blood supply occurs inside body, using peritoneum as a membrane across which waste can be removed catheter (tube) placed through wall of abdomen and 2/3 L of fluid (with blood products and no waste) is passed through tube and wastes in blood diffuse to tube every day

Answer 114

passing blood through dialysis machine blood passes through lots of tubes made of semipermeable membrane and immersed in fluid (no waste) waste from blood diffuses into tubes 4-5 hours for 3 times per week

Answer 115

transplantation of kidney into a patient with end stage kidney disease (kidneys lose 90% ability to functions properly) only one kidney needed ``` adv: better quality of life lower death risk fewer dietary restrictions lower treatment cost ``` ``` disadvantage: risk of infection risk of blood clots and bleeding failure or rejection of donated kidney *after kidney is transplanted-> you need to take anti-rejections drugs or immunosuppressant drugs ```

Answer 116

1. provides a firm framework that gives shape to the body and supports the internal organs. 2. Articulation (movement) anchor points for muscle. skeleton determines extent of movement of body parts 3. protection of vital organs 4. bones act as storage organs for mineral salts and fats (Ca, P, Na, K). distributed via circulatory system when required 5. blood cell production. red bone marrow has stem cells that can differentiate into blood cells. which cell is produced depends on the bodily factors

Answer 117

1. diaphysis: shaft makes up main part of bone. hollow cylinder of compact bone surrounding a cavity. cavity filled with yellow bone marrow which is a fat storage site. 2. epiphysis: enlarged ends of bone, covered by articular cartilage. have compact bone on the outside but their central regions contain spongy or cancellous bone (more porous with large spaces filled with marrow-may contain red bone marrow) 3. periosteum: dense, white, fibrous cartilage covering on the outside surface of the bone. no periosteum on joints where bone is covered with articular cartilage

Answer 118

bone is classified as connective tissue (cells w matrix) l-> inorganic salts in matrix increase rigidity, strength and hardness) single units called osteons/Haversian canals

Answer 119

centre of each osteon is a central canal around which are lamellae (concentric layers of bony matrix) between lamellae are small spaces in matrix called lacunae (bone cell occupies each lacunae) projectuions from each bone cell enter canacliculi (tiny canals)and make contact with adjacent bone cell (materials passed) central canal contains at least one blood vessel, (or lymph vessel and nerves)

Answer 120

run parallel to the long axis of the bone giving it maximum strength lamellae surround Haversian canal

Answer 121

not organised into osteons. consist of an irregular arrangement of tiny bony plates called trabeculae. bone cells occupy spaces in trabeculae, but lamellae are not organised in concentric layers and nerves and blood vessels pass through irregular spaces in the matrix found only in epiphysis region.red bone marrow confined to these cavities epiphyseal lines of cartilage are remnants of plate seen in young growing bones

Answer 122

1. shape - long: femur - short: carpals/tarsals - flat: scapula, sternum - irregular: pelvis - sesamoid: develop in tendons, patella 2. structure: - compact bone: dense, thicker, harder - spongy/cancellous bone: porous, many large spaces, filled with yellow or red marrow and has network of bony plates (trabeculae)

Answer 123

shaft called diaphysis medullary cavity filled with yellow bone marrow that stores energy as fat ends called epiphysis thin layer of cartilage (articular hyaline cartilage) covers each epiphysis to reduce friction at the joint

Answer 124

brittle calcified matrix (calcium phospate) increase hardness while collagen fibres give bone a degree of pliability

Answer 125

young cells that produce bone | forms bone matrix (calcium phosphate and collagen fibres)

Answer 126

formed from osteoblast mature bone trapped in matrix maintains bone tissue

Answer 127

reabsorbs/destroys bone tissue releases acidic enzymes to dissolve bone and make cavities during growth and healing active during ageing

Answer 128

bone formation and remodelling | bones of skeleton are formed from hyaline cartilage oin embryo by ossification

Answer 129

1. hyaline: closlely packed fine fibres (collagenous) in matrix. chrondocytes seen in lacunae - strength and flexibility - rings of trachea and bronchi, end of bones 2. elastic: elastic and collagen fibres not so closely packed, flexible/elastic support - ear cartilage 3. fibrocartilage: thick collagenous fibres allows for compression supports body weight and endures heavy compression -intercollated discs between vertebrae - knee joint - connecting pubic bones no blood vessels in cartilage *nutrition and waste removal for cells is through diffusion through matrix-> slow process chrondocytes have slow metabolism (slow cell division)-> slow healing process

Answer 130

site where two or more bones come together some are rigid (tightly fit) some allow bones to move in relation to each other (loosely fit)

Answer 131

1. fibrous: no movement between bones (fit tightly together) held in place by fibrous connective tissue -sutures of skull hard to break, bone fracture before the joint ``` 2. cartilaginous held in place by cartilage, slight movement -between vertebrae -pubic symphysis - between ribs and sternum ``` 3. synovial: freely movable, movemnt limited by ligaments, tendons muscles and adjoining bones has s cavity between articular cartilage surfaces of bone, covered with s membrane

Answer 132

1. ball and socket joint can move in 360º plane (back to forth, side to side, rotation) - hip, shoulder 2. hinge joint: back and forward -knee, interphalangal, elbow 3. pivot (trochoid/rotary) rotation -vertebrae -radioulnar in wrists and elbow 4. gliding side to side, back to front -between ribs and vertebrae -base of thumb 5. condyloid: back and forward, lateral (similar to hinge) -wrist joint -between phalanges and metacarpals/metatarsals 6. saddle joint: back and forward, side to side, some rotation -thumb

Answer 133

articular capsule surrounds and encloses the bone 1. the fibrous outer layer capsule (made of dense fibrous connective tissue) attached to the periosteum. Flexibility permits motions and strength avoids dislocatio. hold bones together. 2. synovial membrane: makes up inner layer of capsule. loose CT and lots of blood capillaries. lines entire joint except articular cartilage and articular disc

Answer 134

``` flexion (decrease angle between bone) extension (increase angle between bone) abduction (movement away from midline) adduction (movement towards midline) rotation (movement around long axis) ```

Answer 135

within matrix are spaces that contain cartilage cells (chrondoblasts), the produce matrix and gradually become surrounded by it until they are trapped in small spaces called lacunae (chrondocytes) variation of fibrous structure of cartilage classifies it into three types

Answer 136

secreted by synovial membrane and fills synovial cavity lubricates joint and provides nourishment contains phagocytic cells that remove pathogens keep surface of bone from touching, small amount that coats increase fluid means swelling

Answer 137

covers articulating surfaces of bone forming the joint | smooth surface for movement

Answer 138

``` in knee (meniscus) split cavity in two to direct fluid into areas of greater friction ```

Answer 139

little sacs of synovial fluid | prevent friction between bone and ligament/tendon or bone and skin

Answer 140

holds the bones together in many joints

Answer 141

when loss of bone mass with ageing becomes sufficient to impair normal functioning l-> minor injuries could lead to serious fractures need to increase calcium intake, vitamin D, exercise and quitting smoking

Answer 142

joint cartilage deteriorates and bone surface is no longer protected exposed bone begins to wear way and bony spurs/growths may develop from exposed end of bone that forms the joint, the spurs decrease space in joint cavity which restricts the movement symptoms: pain and stiffness in joints (more severe after pressure applied or exercise), crackling sound when they move no cure joint replacement surgery

Answer 143

sections of DNA that contain genetic code. store information that determines the activities and structure of the cell consists of up to 1000 bases, possibilities are enormous

Answer 144

dna strands are bound to proteins called histones. each DNA is coiled around the histones so long molecules can fit into a small space when a cell is about to divide, the coiled chromatin becomes even more tightly coiled to form chromosomes

Answer 145

deoxyribonucleic acid found in nucleus of the cell | contain genetic information that determines the structure of a cell and how it functions

Answer 146

1. double stranded DNA molecule unwinds and units by helicase (enzyme), and weak hydrogen bonds are broken 2. primase is required to initiate/start replication. The primer helps DNA polymerase to know where to start copying 3. DNA polymerase: binds to a single strand and helps create/build a complementary strand (using free nucleotides in nucleus) to know where to start copying 4. ligase is needed to glue/seal DNA fragments together 5. the DNA molecule is formed has one strand of the original parent DNA and 1 newly made strand

Answer 147

1. takes place in the nucleus 2. triggered by hormone that enters nucleus and binds to specific gene on DNA 3. RNA polymerase then attaches to begin the process 4. helicase makes the double stranded DNA molecule unzip to allow one of the DNA strands to be decoded (template strand) RNA polymerase transcribes the bases on the template strand to make a complementary molecule of mRNA (uracil) 5. mRNA nucleotides floating around in the nucleus find their complement on the DNA strand and bond to gather due to base pair rule sequence of bases tell RNaA polymerase to stop copying this release mRNA molecule 6. once the DNA segment has been copied by the mRNA bases, the mRNA strand separates from the DNA. mRNA contains complementary base sequence to original DNA 7. introns are removed (Junk DNA) 8. the mRNA leaves the nucleus via pore and enters the cytoplasm. it attaches to a ribosome for protein synthesis 9. DNA zips up again to create the original double helix

Answer 148

1. takes place at a ribosome 2. mRNA is read 3 codons at a time. AUG is the start codon, ribosome start making protein, methionine can be removed later 3. tRNA delivers AA to the ribosomes, each tRNA carries a specific AA. the tRNA anticodon, will match with its complementary mRNA codon 4. ribosome works its way down the strand of mRNA reading off the code. (tRNA is recycled, bringing in more AA) rRNA join AA together by forming a peptide bond 5. as process continues, polypeptide chain is formed until a stop codon 6. multiple copies of proteins are made as other ribosomes copy the first ribosome 7. mRNA is recycles, broken up and nucleotides reused 8. after translation, proteins are modified by folding and shortening them in a certain way (enzymes) transported to where the body needs

Answer 149

in a cell that isn't dividing, coiled DNA form an untangled network called chromatin

Answer 150

building blocks are called nucleotides each DNA consists of two strands of alternating sugars and phosphates with pairs of nitrogenous bases forming cross links between sugar molecules in the two strands twisted into spiral shape (double helix) base contains nitrogen atoms, bond between bases are weak hydrogen bonds

Answer 151

two linked chains in DNA separate because bond between bases is weak each separated sections half of the original and acts as a template for for nucleotides that form the other half using complementary bases

Answer 152

amino acids joined to form chemical bonds that hold, AA together joined in ribosome in cytosol of cell. DNA is too big to leave the nucleus so mRNA is used as it is small enough to go through nuclear pores conversion of genetic code carried by DNA to an end product (protein)

Answer 153

types of protein a cell makes is determined by it gens. different genes are activated in different cells (insulin) triplet codes for amino acids that are joined together at ribosomes

Answer 154

8 part histone structure

Answer 155

photograph of chromosome organised by size shape and banding

Answer 156

no genes to carry out instructions | made by enzymes (proteins) indirectly controlled by genes

Answer 157

in mitochondria small circular molecules has 37 genes 24 genes code for making tRNA molecules, 13 genes are instructions for making enzymes needed to make ATP provides information which is needed for mitochondria to function

Answer 158

cells and mitochondria are codependent inherited from mother as mDNA in sperm are destroyed in fertilisation used for ancestry, evolution and forensics disease: inability to produce sufficient energy to carry out simple tasks

Answer 159

study of changes in gene activity that don't involve changes in gene code epigenome: second set of instructions that interact with DNA that activate/suppress expression of certain genes exposure to certain stimuli can change epigenome

Answer 160

add acetyl group | cause DNA to unwind enhancing gene expression

Answer 161

adding a methyl group | cause DNA to coil more tightly silences or switches of gene

Answer 162

G1 phase: first growth, cells produce new proteins, grows and carries out its normal tasks S phase: synthesis, DNA duplicates itself G2 phase: second growth, short phase that involves preparation for cell division M phase: mitotic, cell divides into two daughter cells some cells leave cell cycle and stop dividing for years or rest of life. G0

Answer 163

period between nuclear divisions G1,S,G2 DNA replicates

Answer 164

centrioles become visible early on, move to opposite ends of cell (poles) and microtubules radiate from them form framework of fibres called spindle nucleolus disappears and nuclear membrane breakdown chromatin threads of DNA coil to be seines chromosomes (2 chromatid joined at centre with centromere) chromatids are identical to each other and tightly coiled coiling makes it easier to distribute DNA to daughter cell migrate to equator of cell

Answer 165

chromatid line up at equator | centromere of each pair is attached to a spindle fibre

Answer 166

each pair of chromatids separate at centromere | new chromosomes are pulled apart towards opposite poles of cell

Answer 167

two sets of chromosomes form tight groups at each pole nuclear membrane forms around each group and nucleolus appears spindle fibres disappear chromosomes gradually uncoil to become chromatin

Answer 168

while telophase occurs, cytoplasm begins to divide | furrow develops between two nuclei and deepens til it is cut in two

Answer 169

all cancers have common characteristics when a tumour results form uncontrolled division of cells, don't differentiate so the cancer cells can be identified malignant: cells spread throughout the body benign: don't spread to other parts of body but can press on surrounding tissues carcinogen: factors that can trigger cancer (UV, Xray, HPV, ionising radiation, chemicals)

Answer 170

caused by HPV, transmitted through genital skin contact during sex Pap test: cells from cervix detect changes in cells that may develop into cancer

Answer 171

mammogram: Xray picture that detects tumours, even really small ones

Answer 172

in large intestine FOBT faecal occult blood test: detects traces of blood caused by polyps/ cancer. polyps can lead to cancer Colonoscopy

Answer 173

no screening DRE, digital rectal examination: feeling prostate for irregularities PSA, prostate specific antigen:checks blood for a specific protein produced by prostate gland rising levels can indicate tumour biopsy: small sample of tissue that can be checked for cancer cells

Answer 174

primary sex organs | produce gametes

Answer 175

store gametes bring them together for fertilisation support developing baby

Answer 176

male gonad, oval shaped produces spermatozoa held and supported in aa skin covered pouch, scrotum, internally divided into 2 sacs each containing a single testis testes lay outside body cavity because production of sperm a temperature that is 2º less than the regular body temperature. contraction of smooth muscle fibre in scrotum wall, moves testes closer to body at a higher temp. Relaxing fibres moves testes away, making it cooler. divided into around 200 and 300 lobules filled with fine tubes called seminiferous tubules. tubules are lined with cells that make sperm. clusters of interstitial cells between tubules secrete testosterone

Answer 177

the seminiferous tubules in each tubule/compartment of a testicle join to gather to form a short straight tubule. straight tubule eventually join into ducts which leave the testicle and lead to the epididymis highly folded tubule at the rear surface of each testis. unraveled= 5-6m, allows for lots of space for sperm storage, can be held form months, during this time, sperm mature

Answer 178

tubule of epididymis continues to become the vasa deferentia. carries sperm away from testis. loops behind the bladder and under the bladder the two tubes going the urethra.

Answer 179

nourishes and aids the transport of sperm, semen contains enzymes that activate sperm once ejaculation takes place. 1. seminal vesicle: pair of vesicles behind the bladder. secrets a thick fluid rich in sugars, makes up 60% of semen volume. 2. prostate gland: surrounds urethra below bladder. secretes a thin milky alkaline fluid that becomes part of semen 3. bulbo-urethral glands: pea sized small yellow glands, behind prostate on either side of the urethra. secrete clear mucus which is carried to the urethra by a duct from each gland. act as a lubricant, only a small amount in semen

Answer 180

penis contains connective tissue very rich in blood supply | the erectile tissue has a large number of sponge like spaces that fill with blood when sexually aroused (erection)

Answer 181

each side of abdominal cavity, supported by ligaments composed of a mass of connective tissue called stroma, which is surrounded by a layer of cells including germ cells (gametes) each germ cell is enclosed in a follicle, numerous follicles are at different stages of development at any time. as a follicle matures, it moves to the surface of the ovary and ruptures

Answer 182

egg is expelled into funnel like opening of FT 2 FT, one extending from each ovary carry egg from ovary to uterus fimbriae: funnel like opening of FT is lined with finger like projections that appear to touch the surface of ovary. help guide the egg into tube ciliated epithelium lines the tube. beating cilia and contractions of smooth muscle that lines the tubes help the egg move.

Answer 183

pear shaped organ behind the bladder, in front of rectum held in position by broad ligaments, they don't hold the uterus tightly in place, has limited movement so position can vary slightly wall is made of smooth muscle with a soft mucous membrane lining (endometrium) protects and nourished foetus during pregnancy

Answer 184

lower end of uterus, protrudes into vagina

Answer 185

muscular structure lined with mucus membrane, capable of considerable stretching external opening of vagina is partially covered by a fold of tissue (hymen) vulva (external genitals)= labia majora+labia minora +clitoris

Answer 186

labia majora: fleshy fold of skin made of fat and fibrous tissue. glands that produce oily secretions. outer part is hairy, inner part is smooth labia minora: smaller folds of skin, beneath and between the labia majora. surrounds external opening of vagina and urethra clitoris: contains erectile tissue, blood vessels and nerves engorged with blood when stimulated

Answer 187

production of gametes with half the number of usual chromosomes, makes 4 daughter cells occurs in gonads involves two nuclear divisions but chromosomes duplicate only once

Answer 188

during interphase DNA is copied Prophase 1: chromosomes become visible as two chromatids homologous pairs lie next to each other crossing over occurs (exchange of genes) spindle fibres form and nuclear membrane disappears Metaphase 1: paired homologous chromosomes line up along equator independent/random assortment of maternal and paternal spindle fibers attach to each Anaphase 1: pairs separate and homologous move to poles (23 each side) Telophase 1: nuclear membrane reforms around 23 chromosomes cytoplasm divides in two 2 haploid daughter cells with a different combination of maternal and paternal genes

Answer 189

interphase is skipped Prophase 2: centriole migrate and new spindle fibres form nuclear membrane disappears Metaphase 2: chromosomes move to equator and line up spindle attaches to chromosomes Anaphase 2: chromatids spilt and move to poles Telophase 2: nuclear membrane reforms cytoplasm divide

Answer 190

seminiferous tubules of each testis are lined with immature cells called spermatogonia (diploid) at puberty the spermatogonia divide by mitosis to make continuous source of new cells for the production of sperm. Some daughter cells are pushed to the centre of the tubule where they undergo a period of growth. These enlarged cells other primary spermatocyte. They are diploid and undergo meiosis 1 to form secondary spermatocytes (haploid). secondary meiosis occurs which divides the secondary spermatocyte into two spermatids. 4 haploid cells produced. spermatids mature in to sperm for the final stage. much of cytoplasms, of cells is lost and a tail made of contractive material is formed. nourished by special cells takes 72 days and occurs continuously after puberty

Answer 191

head: contains nuclear material, with a fluid filled vesicle at the tip. contains enzymes that breaks down ovum's outer layer middle: contains mitochondria, allows respiration take place to produce energy for sperm to move. has a little cytoplasm, so has a short life. tail: capable of violent swimming to propel cell forward

Answer 192

before birth millions of oogonia develop in ovaries. decreases to several 100 thousand at birth which have undergone a growth phase to make primary oocytes, they begin prophase 1 but stops there. each primary oocyte is surrounded by a primary follicle. puberty: follicle growth and maturation begins as follicle matures, the primary oocyte complete meiosis 1, producing two haploid cells that are unequal in size. one secondary oocyte (half chromosomes but almost all the cytoplasm) and first polar body. secondary meiosis is commenced by the secondary oocyte but stops at metaphase 2 (ovulation occurs at this stage). follicle ruptures expelling secondary oocyte and polar body. SO enters FT and if fertilised, meiosis 2 is completed. meiosis 2 also makes two unequal cells. larger one develops into an ovum and smaller one is the second polar body. first polar body may divide, however all polar bodies disintegrate

Answer 193

series of events in ovaries maturation of egg and release into tube development of follicle and corpus luteum 20 - 40 days (28 average) cells in ovaries undergo many divisions but stop dividing before and ovums are actually formed other cells within the ovary surround each immature egg to produce a sphere composed of a single layer of cells (primary follicle)

Answer 194

at puberty some primary follicles undergo further development cells forming wall of follicle begin to enlarge and divide creating a layer of cells around the developing egg secretions of these cells creates a fluid filled space that gradually forces the egg to the edge of the follicle, forming the secondary follicle. several secondary follicles may commence development in each cycle but only one completes development, others may breakdown to be reabsorbed into ovary. as more fluid accumulates within the follicles, it continues to enlarge and gradually moves to the surface of the ovary. on reaching the surface it creates a bulge that looks like a blister. follicle is now a Graafian follicle (mature). takes 10-14 days to make a mature follicle from a primary follicle. when mature follicle bursts, it expels the egg in a process called ovulation

Answer 195

ruptured follicle collapses and blood within forms a clot. the clot gradually absorbed by the remaining follicle which enlarge sand changes colour to a cream, corpus luteum. corpus luteum secrets progesterone for endometrium

Answer 196

CL reaches max development 8-10 days after ovulation, and begins to degenerate intro fibrous mass of scar tissue, corpus albicans which eventually disappears cycle begins over again. from which ovary the egg come is up to chance

Answer 197

CL continues to develop and cycle ceases. CL reaches peak development in the 3rd month, so it slowly begins to degenerate then. cycle resumes after breastfeeding stops

Answer 198

if the egg isn't fertilised, CL degenerates which leads to a decrease in progesterone, so endometrium breaks down. blood from broken down capillaries, mucous secretions and cell debris from uterus lining is lost through vagina. and shedding of endometrium

Answer 199

in females: stimulates development and maturation of the ovarian follicle. during its development, the follicle secretes oestrogen. as oestrogen increase in blood, FSH decreases in males: stimulates epithelial tissue of seminiferous tubules in testes to produce sperm

Answer 200

in males: targets interstitial cells of testes to stimulate secretion of testosterone in females: promotes final maturation of the ovarian follicle, ovulation and production of CL. stimulates secretion of oestrogen and progesterone

Answer 201

development if female reproductive system | development of secondary sexual characteristics

Answer 202

CL secrets progesterone. there is a gradual decrease in LH as progesterone decreases. maintains the endometrium, development and maintenance of the placenta, and development of milk secreting glands

Answer 203

important in developing immature sex cells into mature sperm | sex drive

Answer 204

rhythmic of epididymis, prostate gland, vas defers and seminal vesicle lead to ejaculation erectile tissue in region of vaginal opening fills with blood which reduces size of vaginal opening. secretion of mucus by glands surrounding cervix and vaginal opening lubricate lining of vagina

Answer 205

only few 1000 reach the FT high sperm mortality is why there is a lot ovum: surrounded by a layer of follicle cells (corona radiata ) cells are held together by acid. several thousand sperm need to loosen the cells of corona allowing one sperm to complete fertilisation. forms fertilisation membrane which prevents other sperm to enter. tail is absorbed and head forms male pronucleus. meiosis finishes and nucleus of egg forms the female pronucleus which fuses with the male pronuclei to form a diploid nucleus (zygote)

Answer 206

after fertilisation, the zygote travels down FT and begins to divide by mitosis mitosis results in formation of 2 identical cells 2 cells divide again to 4, 8, 16 (cleavage divisions) 6 days after fertilisation, zygote reaches uterus and develops into blastocyst b: hollow ball of cell that surround a cavity filled with fluid. at one side of cells cavity is the ICM ICM: group of 30 stem cells, that will develop into embryo blastocyst remains free in cavity of uterus for 2-3 days before it embeds in endometrium to become firmly attached to uterus wall

Answer 207

stem cells: 1. not specialised for any particular function 2. capable of repeated division by mitosis 3. can differentiate into specialised cells proliferation: when cells replicate themselves many times over differentiation: when unspecialised cells develop characteristics and functions of particular types of cells. as stem cells proliferate, different types genes become activated that allow differentiation internal signals: controlled by genes external signals: chemicals released by other cells, contact with other cells, molecules in cell's microenvironment

Answer 208

give rise to all cell types that make up human body, any cell necessary for embryonic development give rise to all cell types that make up membranes that surround developing embryo early embryo before formation of ICM (undergo several rounds of cell division then after 5 days specialise into blastocyst) outer layers form placenta + other tissues

Answer 209

can give rise to all cell types that make up body, but not all cell types that make up embryonic membranes ICM

Answer 210

exist in embryo and adults give rise to cells that have a specific functions more than one but not all blood stem cell

Answer 211

continued development of blastocyst depends on endometrium being maintained. high levels of hormones stop endometrium breakdown (menstruation) early pregnancy corpus luteum maintains endometrium til placenta takes over first 2 months=embryonic period after is called foetus

Answer 212

While implantation of blastocyst, ICM undergoes changes that develop 3 cell layers 1. endoderm 2. medoderm 3. ectoderm

Answer 213

epithelium of alimentary canal and its glands epithelium of bladder, urthera and gall bladder epithelium of pharynx, larynx, trachea bronchi and lungs

Answer 214

skeletal smooth and cardiac muscle cartilage, bone, blood and other connective tissue dermis of skin

Answer 215

epidermis of skin hair, nails, skin glands teeth enamel entire nervous system

Answer 216

early in embryonic period: 4 membranes form that lie outside embryo to protect and nourish 1. amnion: 8th day after fertilisation. surround embryo and enclose cavity where it secretes fluid. fluid: protect against physical injury, maintain constant temp and free movement 2. chorion: formed from outer blastocyst cells and layer of mesodermal cells. surrounds embryo and three other membranes as amnion enlarges it fuses with inner part of chorion and eventually becomes main part of foetal part of placenta 2 other membranes become part of umbilical cord

Answer 217

formed by three months foetal part begins forming at implantation. small branching fingerlike projections form from outer layer of cells (numerous blood vessels form in the projections) and grows into endometrium as chorionic villi penetrate endometrium they become surrounded by mother's blood which has collected in spaces in endometrium foetal and maternal blood don't mic because few layers of cells separate the two. exchange of material takes place by diffusion and active transport placenta attached to foetus by umbilical cord. 2 umbilical arteries (to placenta) blood enters maternal side of via uterine arteries to blood spaces

Answer 218

organ that supplies nutrients to foetus 1. endocrine: secretes hormones necessary to maintain pregnancy 2. excretory: transports nitrogenous wastes from foetal blood to mother's blood supply to mothers kidneys 3. immune: transport antibodies from mother into foetus 4. nutritional: stores essential nutrients early in pregnancy and release when demand is greater 5. respiratory: transport o2 and co2

Answer 219

muscle segments on either side of neural tube. blocks of mesodermal tissue increase over time to represent beginnings of muscle and vertebrae of spinal column Brain, heart and liver begin forming clefts in throats begin developing. pharyngeal arches form structural elements of face and throat. pouches that develop in clefts make epithelial lining and glands of throat 5th week arm and leg bud start appearing recognisable human form

Answer 220

umbilical cord and placenta SC: can be extracted once baby is born, extracted from discarded tissue multipotent and stored in case baby has bone marrow/blood diseases (leukaemia/anaemia) embryonic SC: from frozen embryos from IVF clinics unused embryo can be given to research but requires destruction pluripotent (maybe rejection by patient body) adult SC: patients own cells used but most adult SC are prespecialised mulitpotent

Answer 221

at blastocyst stage of development ICM transferred to culture dish with nutrient solution subcultured to make stem cell line therapeutic cloning: patents cell but in fertilised egg with no nucleus -> develops into blastocyst -> clone

Answer 222

3cm to 50cm 4g to 3400g month 3: sex distinguishable and forelimbs well developed month 4: arms and hands full shaped, Skelton completed, exercising of muscles evident month 5: fine hair covers body, gripping reflexes develop, movement detected month 6: respiratory movements, tooth buds evident, digestive glands begin to function month 7: all systems functional expert respiratory month 8: accumulation of fat beneath skin month 9: eyes open, nose well formed, sucking and grasping reflexes apparent and fine body hair shed shortly before birth: foetus rests head inside curved shape of pelvis, movement restricted and placenta starts to fail and become fibrous antibodies diffuse through placenta

Answer 223

due to growing abdomen, other organs are forced up and out enlargement of breasts: hormones result in development of milk secreting tissues increase in heart size and blood volume increase blood flow to kidney and urine production, pressure on bladder mothers functions slow down to allow nutrients to stay in blood for longer weight gain: hormonal changes promote conversion of energy to fat and retention of water

Answer 224

need to increase energy intake, calcium, iron, folic acid fluoride helps protect against future dental problems exercise to maintain stamina during labour progestin to insure full term pregnancy

Answer 225

congenital disorder: present at birth (mutation or inherited gene) teratogenic agent: cause physical defect in embryo

Answer 226

rubella: viral infection. if contracted by mother, child may be born deaf, blind or with heart malformations

Answer 227

folic acid: essential for normal cell division and manufacture of protein. 1 month before and 3 months lack can lead to spina bifida: bony arch or vertebrae around spinal cord doesn't develop calcium: bone growth vitamin A: normal cell growth listeriosis: eating food contaminated by listeria monocytogenes. cause miscarriages or still birth eat freshly prepared food and avoid soft cheeses, seafood, pate and pre package salads

Answer 228

FAS: effects of feta exposure to exessive alcohol intake slow growth narrow eye slits and sunken nose bridge heart defects mental retardation, slow attention span

Answer 229

lower birth weight increased risk of abortion breast feeding: gastrointestinal problems and respiratory problems (bronchitis, pneumonia) increased risk of SIDS

Answer 230

limb malformations between day 28 and 42 when limbs are coming affects arms more than legs

Answer 231

inaudible high frequency sound waves to make foetus image sound waves reflected by foetal tissue to obtain a visual echo detects: brain, head, limbs malformations and spina bifida

Answer 232

small telescope introduced through abdominal wall | examine appearance

Answer 233

using karyotype to see if any chromosomal disorders are present amniocentesis: 16-20 weeks when there is 130ml of fluid. removes 10-20ml of amniotic fluid and takes floating foetal cells. spina bifida chorionic villus sampling: obtain specimen of foetal cells from chorion. 9-19 weeks and tested quickly. 2% miscarriage mother blood: simpler sample treated with special antibodies that adhere only to fetal cells in mother's sample magnetic beads isolate from other cells

Answer 234

foetal blood directly obtained and quicker results | PUBS: foetal blood extracted from umbilical vein using thin needle through abdominal wall

Answer 235

regular recording of baby's heart to detect stress | ECG: identify risk of injury to foetus and check if chance of o2 deficiency

Answer 236

assessment of marker proteins. PKU: increased amounts of phenylalanine in blood or phenylpyruvic acid in urine AFP in amniotic fluid = spinal cord malformation

Answer 237

DMD and thalassaemia segment of DNA identical to tested gene, some units in segment are labelled. DNA probe joins with gene being tested: if gene is normal probe joins with gene that is structurally identical and shows up if abnormal gene doesn't show up. gap in DNA being tested

Answer 238

spem donated risk of transmission each day of ovulation (3-4) 3 inseminaton /month for 3 month

Answer 239

IVF: implantation of fertilised egg GIFT: gametes mixed and before they fertilised it is transferred to fallopian tubes ICSI: low sperm count, single sperm injected into egg. embryo implants din uterus 20-30% donor egg: unable to conceive own eggs. fertilised egg implanted surrogacy: unable to be pregnant

Answer 240

several hormonal changes cause pelvic ligaments soften to become more pliable for childbirth, also increase response of uterus to stimulus and strengthen contractions of muscle foetus settled with head in mothers pelvis cervix softens, shorter in length, likely to open a little foetus usually faces woman r/l hipbone with its knees drawn up to abdomen (takes up minimal room) one side of head against bowel, other against bladder

Answer 241

during final 3 months of gestation, uterus has weak irregular contractions, stronger during final weeks, eventually become occur every 30 minutes start of labour to completion of cervix dilation foetus moves deeper into pelvis waves of contraction travel from upper uterus to cervix (like peristalsis) with each contraction, uterus muscle fibres shorten and pull on cervix causing it to shorten so it no longer projects into vagina as contractions become more frequent and stronger, foetus head pushed more against dilated cervix fully dilate = 10cm, uterus cervix and vagina become one curved passage (birth canal) foetus passes with help of uterus contractions and voluntary abdominal contractions from mother

Answer 242

expulsion stage usually begins with bursting of membrane surrounding foetus leading to gush of fluid from vagina (can happen earlier) 20 minutes to 2 hours as foetus moves through canal it head stretches vagina distention of vagina forces woman to push. contractions of uterus and mother push foetus through vagina and baby's head turn to face mother's back each contraction pushes baby through head moves to external vaginal opening and stretches opening and tissues between it and anus head forced out, once head emerges, it turns sideways to face mothers hips, the rotation allows for easy movement head is downward for 90% of births and acts as a wedge to force open cervix vagina and allows baby to begin breathing before completely out as foetus is pushed out, pressure on head may cause it to be pushed out of shape, doesn't damage brain and resumes normal shape sutures of skull are pliable and allow for some overlap

Answer 243

baby breathes even though it is connected to placenta amnion chorion and placenta are still inside umbilical cord clamped and tied between two places and cut between ties arteries and vein contract before and after cut, after a few days cord dries and falls away (navel) at birth: baby is covered in vernix which is a protective layer. thin layer kept as it decreases risk of skin infection after 5 minutes uterus contracts and placenta, other membrane and part of umbilical cord are expelled in the afterbirth little blood loss: placental blood vessels constrict and uterus contractions squeeze shut uterine vessels tats apply blood to placenta blood clots form to stop leakage *risk of infection

Answer 244

head is 1/4 length, legs 1/3 held vertically: head drops and legs hang because muscle control hasn't developed reflexes govern most of movement

Answer 245

infant must become self supporting as foetus: blood return to foetus via umbilical vein some blood flows through liver and IVC. remainder bypasses liver by flowing through DUCTUS VENOSUS then into IVC blood returning to foetal heat enters right atrium then... 1. right ventricle to lung but lungs arrest functioning and offer resistance so little blood flows that way 2. through DUCTUS ARTERIOSUS to aorta. lung bypass that allows blood in pulmonary artery to flow directly to aorta 3. into left atria through oval opening between chambers, FORAMEN OVALE, beneficial because placental blood is rich in oxygen and flows to developing foetal tissues via aorta quickly at birth: 1. DUCTUS ARTERIOSUS: the first breath stimulates respiratory system to function so it doesn't show resistance to blood flow, so little blood flows through the DA. DA degenerates to fibrous tissue 2. as more flood return to heart through lungs, pressure in left atrium increase so the flap of the FORAMEN OVALE is permanently forced closed against atrial wall if FO is still open surgery must be performed 3. cutting umbilical cord means that no blood flows through the umbilicus vessels or DUCTUS VENOSUS so it gradually constricts til closed. liver bypass I lost so it must start functioning initially breathing and heart rate is high because more o2 is needed for increased muscular activity and thermoregulation

Answer 246

puerperium:uterus returning to no pregnant state (8 wks) painless contractions and non abdominal swelling shrinking from contractions and gradual shrivelling of muscle fibres which flatten abdomen discharge of fluid: blood and breakdown products of tissues that is discharged as uterus shrinks decrease in blood volume, slower pulse, higher temp day 3 depression if mother breast feeds, menstruation delayed for 6 months not breast feeding around 10 weeks

Answer 247

breast contains 16-25 sections called lobes which are divided into lobules, walls of each lobule made of glandular alveoli (milk secreting region) lobes and lobules surrounded by fatty connective tissue from lobule, ducts open into wide spaces (milk space) reservoir for milk made by the alveoli from each space short straight duct leads to the nipples, 15-25 openings on nipple as each lobe has its own milk space

Answer 248

lactation: initiation and maintenance of milk secretion and delivery of milk to baby early in pregnancy increase in hormones cause more complex and large lobes and oil secreting glands around nipple to enlarge a day or 2 after milk secretion 1st secretion colostrum (watery yellowish white fluid) little to no fat, high in mother's antibodies that give baby temporary immunity once nipple is sucked, milk let down reflex triggered 1. nipple sucked, nerves in nipples stimulated and sent to brain 2. posterior part of pituitary gland releases oxytocin in blood 3. causes tiny muscles around lobules to squeeze milk into nipple openings

Answer 249

legs grow rapidly | head and face grows slowly than body as a whole

Answer 250

examining incidence of disorder in pedigree

Answer 251

identify genetic makeup, fingerprint special enzymes: DNA cut at specific base sequence leaving pieces of various lengths. length varies each person gel electrophoresis: 1. DNA placed in bed of semisolid gel 2. electrical currents pass through gel via electrode at each end 3. negatively charged DNA moves towards positive electrode 4. smaller DNA moves faster, resulting in a banding pattern marker: segment of DNA with known characteristics used as point of comparison. more that match =closer relation

Answer 252

random assortment: when two gametes unite at fertilisation, resulting cell has different combination of genes. 1st meiotic division homologous chromosomes separate at random, not influenced by other. 2^23 each egg crossing over: during prophase of meiosis 1 sections of DNA exchanged cross at chiasma chromatids become tangles. pieces break off, swap and reattach different alley combination (recombination) non disjunction: when homologous chromosomes or chromatid pair fail to separate. one cell has too many, other has too few/ dramatic birth defects partial trisomy: extra chromosome attached to other chromosome random fertilisation: fertilisation is a random event, any sperm with any egg epigenetic and inheritance:

Answer 253

``` autosomal dominant lack of control over muscles, progressive mental deterioration symptoms appear 30-40 involuntary flying of arms and legs dementia hard making voluntary movements ```

Answer 254

autosomal dominant dwarfism short limbs, prominent head, waddling gait

Answer 255

autosomal dominant affects facial muscle other gradually affected

Answer 256

``` autosomal dominant numerous tumours along peripheral nerves composed of dense proliferation fo nervous and fibrous tissue cause abnormalities of skin + flesh distortions to bone structure ```

Answer 257

autosomal recessive | anaemia from defects in formation of HGB

Answer 258

autosomal recessive controls production of enzyme (phenylalanine hydroxylase) that turn phenylalanine to tyrosin phenylalanine build up in blood and is toxic (mental retardation, seizures and not normal skin pigmentation ) special diet required

Answer 259

autosomal recessive chest infections, lack of digestive enzymes, increased salt loss diet: low fat, high carb + protein

Answer 260

autosomal codominant abnormal HGB, RBC misshapen and blood can't carry normal o2 levels Heterozygous: normal RBC unless there is a low concentration of o2 in blood. malaria resistant

Answer 261

autosomal recessive disorder of lipid metabolism missing enzyme which leads to accumulation of fatty substance in nervous system death early in childhood

Answer 262

X linked recessive | blood clots slowly or not at all

Answer 263

X linked recessive kidneys unable to concentrate urine passes large quantities of urine death if water needs aren't met

Answer 264

X linked recessive progressive wasting of voluntary muscles muscle tissue wastes away and replaced by fatty substances wheelchair to bedridden to respiratory failure

sem 2 exam Flashcards

(288 cards)