ch6: idk why yennefer wants her womb back so much tbh Flashcards
(43 cards)
draw a labelled diagram of the digestive system (4)
google docs
oesophagus: connected to top of stomach
stomach: connected to small intestine
small and large intestines: connected to each other
liver shown as larger than the stomach with gall bladder shown under liver
gall bladder: connected to the small intestine via bile duct
pancreas: connected to small intestine via pancreatic duct
draw a labelled diagram showing the interconnections between the liver, gall bladder, pancreas and small intestine (2)
google docs
describe the digestion of food in the human digestive system (6)
digestion begins in the mouth
chewing food → smaller parts → ↑ surface area
starch breaks down to maltose by amylase
proteins break down to polypeptides by pepsin in the stomach
HCl provides optimum pH medium for enzymatic activity
churning in stomach causes mechanical digestion by mixing the enzymes & food
bile salt secreted from gallbladder to emulsify lipid droplets
pancreas:
secrete endopeptidase to break down polypeptides into amino acids
secrete pancreatic lipase to break down lipids into glycerol & 3 fatty acids
secrete pancreatic amylase to break down maltose into glucose
secrete sodium bicarbonate to neutralise acidic chyme to pH 8 for optimum pH medium for enzymatic activity
some final digestion into monomers is associated with epithelial cells of small intestine
peristalsis mix food with digestive juices
circular muscle contraction prevents backward movement of food
longitudinal muscle contraction moves food along gut
outline the digestion, absorption and assimilation of proteins in humans (6)
proteins must be digested into smaller molecules for absorption
protein → polypeptides by pepsin secreted by the stomach
pH 2
polypeptide → amino acids by pancreas secreted by the pancreas
pH 8
amino acids are absorbed into capillaries by diffusion and active transport through the villi and microvilli in the small intestine
blood carries amino acids thru the body → diffuse or absorbed into cells by active transport
assimilation: amino acid becomes part of cell
cells use amino acid for protein synthesis in ribosomes
explain the importance of enzymes/hydrolysis to human digestion (8)
digestion = the breakdown of large molecules → small molecules
for diffusion & absorption → bloodstream → cells
physical breakdown is not enough → need chem breakdown of food
enzymes are required to ↑ rate of digestion
biological catalyst
allow digestion to occur at body temp
enzymatic digestion is a sequential process
amylase: polysaccharides → disaccharides → monosaccharides
starch → maltose → glucose
protease: protein → polypeptides → amino acids
lipase: lipid → triglyceride → glycerol & 3 fatty acids
specific location for each reaction with specific conditions
diff enzymes have diff optimal pH
e.g. stomach pepsin pH 2
most enzymes work extracellularly
explain how the structure of a villus in the small intestine is related to its function (7)
villus has a large surface area to volume ratio
microvilli ↑ surface area for absorption
thin epithelial layer → short diffusion distance → products of digestion can easily pass thru
channel proteins located in plasma membrane → facilitated diffusion
large number of mitochondria → provide ATP
protein pumps in microvilli membrane → active transport
pinocytosis occurs at epithelial layer
network of capillaries inside each villus
transport absorbed sugars & amino acids away from small intestine → blood flow maintain conc gradient
lacteal transport fatty acids away from small intestine
describe the role of the stomach in digesting proteins (5)
protein digestion begins in stomach
acid env denatures other proteins + kill bacteria + activate pepsin
gastric glands in stomach release digestive juice that contains pepsin
pepsin catalyse protein hydrolysis
hydrolysis breaks large proteins into shorter polypeptides
churning mix pepsin with proteins
explain the relationship between structure and function of arteries, capillaries and veins (8)
arteries:
thicc walls → withstand ↑ blood pressure
narrow lumen → maintain ↑ blood pressure
smooth muscle layer → contract to maintain pressure & reduce friction
elastic fibres in outer layer → give wall strength & flexibility
capillaries:
thin epithelial layer of 1 cell only → short diffusion distance → faster diffusion
extensive branching → ↑ surface area for exchange of materials
small diameter → fit between cells/tissues + ↑ oxygen diffusion from red blood cells
pores → allow lymphocytes/plasma to exit
veins:
thin walls → allow skeletal muscles to exert pressure on it
wide lumen → allow ↑ vol of blood to pass
thin muscle fibres in outer layer → provide structural support
valves → prevent backflow
explain the roles of the atria and ventricles in the pumping of blood (4)
atria collect blood from vena cava & pulmonary vein while ventricles are contracting
pump blood into ventricles
ventricles pump blood into arteries
thick muscular walls → high pressure
left ventricle pump blood to systems
right ventricle pump blood to lungs
heart valves working with atria & ventricles → keep blood moving
explain how circulation of the blood to the lungs and to other systems is separated in humans and what the advantages of this separation are (8)
double circulation: heart has separate pumps for lungs & other systems
deoxygenated blood pumped to the lungs & oxygenated to other organs
kept separate → all tissues receive blood with high oxygen content
each side of the heart has an atrium & ventricle
left ventricle pump blood to system via aorta
right ventricle pump blood to lungs via pulmonary artery
left atrium receive blood from lungs via pulmonary vein
right atrium receive blood from system via vena cava
high pressure blood would damage lungs
high pressure required to pump blood to all systems
pressure of blood returning from lungs not high enough to continue to tissues → has to be pumped again
outline the exchange of materials between capillaries and tissues (3)
molecules move by diffusion down a conc gradient
nutrients move into tissues
gas exchange between tissues & capillaries
waste & excess water move from tissues into capillaries
hormones leave capillaries in target tissues to attach to receptors on cells
endocrine gland tissues release hormones into bloodstream
outline how the rate at which the heart beats is controlled (6)
cardiac muscle contraction is myogenic: contract without stimulation
sinoatrial node (SA node) initiates heart contractions
located in the right atrium
electrical signal to contract transmitted from wall of the right atrium → then through walls of the ventricles
nerve impulses transmit messages to pacemaker
medulla control speed of heartbeat through nerves
one nerve ↑ rate while another ↓ it
adrenal gland produce adrenaline → accelerate heartbeat
part of the fight or flight response
describe the action of the heart in pumping blood (5)
atrial systole:
atria collect blood from veins
SA node sends impulses to muscle to initiate contraction
both atria contract at the same time → blood is pushed through open atrioventricular valves into ventricles
semilunar valves are closed so that ventricles fill with blood
ventricular systole:
ventricle muscles contract
blood is pushed out through semilunar valves → into pulmonary artery and aorta
atrioventricular valves snap close
diastole:
ventricles and atria relax → ↓ pressure
semilunar valves close to prevent the backflow of blood
explain how the direction of blood flow in the heart is controlled (2)
valves prevent backflow of blood
open valves allow blood to flow through
valves open when pressure is higher upstream
atrioventricular valves prevent backflow from ventricles to atria
semilunar valves prevent backflow from arteries to ventricles
closed: allow ventricles to fill with blood
draw a labelled diagram of the human heart showing the attached blood vessels (6)
google docs
right and left atrium: above the ventricles and must not be bigger
than ventricles
left and right ventricle: below the atria, must have thicker walls
than atria
superior and inferior vena cava: connected to right atrium
pulmonary artery: from right ventricle to lungs
pulmonary vein: from lungs to left atrium
aorta: large artery from left ventricle out of heart;
atrioventricular valves: between both atria and ventricles
semilunar valves: in aorta and pulmonary artery
outline the mechanisms of defence against pathogens in humans (7)
1st line:
skin: physical barrier
sebaceous glands secrete sebum
mucous membrane: trap & remove + contain lysosomes that destroy pathogens
stomach acid: extreme pH inhibits growth of pathogens
inflammation: cause swelling and fever to inhibit the pathogen
2nd line: phagocytic leukocytes identify pathogens as foreign → ingest by endocytosis
3rd line: specific lymphocytes recognise specific antigens → clone themselves
produce antibodies that attach to specific antigens → form antigen-antibody complex → stimulate destruction of pathogen
outline how leukocytes defend the body against pathogens (6)
recognise pathogens → phagocytes engulf pathogens by endocytosis
migration to tissues by squeezing out of capillaries
each pathogen has a specific antigen:
lymphocytes produce antibodies by reacting to the specific antigen
lymphocytes make clones by mitosis & ↑ total no. of specific antibodies
antibody joins to specific antigen & destroys them
outline how antibiotics offer protection from certain forms of infectious disease (4)
kill/inhibit bacteria growth
bacteria processes blocked but not processes in eukaryotic cells
block metabolic pathways, DNA replication/transcription/translation, ribosome functioning, cell wall formation
do not protect against viruses bc no metabolism
antibiotics fail to protect if bacteria have resistance
discuss the cause, transmission and social implications of AIDS (8)
cause: by HIV: AIDS is observed syndrome when final stages of infection develop no. of lymphocytes ↓ over years ↓ immunity other illnesses develop
transmission:
body fluids from an infected person transmits HIV, which could progress to AIDS
transmitted by blood transfusions, sharing needles, sexual intercourse
can be prevented by using condoms correctly
transmitted from mother to child across the placenta, during childbirth & breastfeeding
↑ incubation period → no awareness of infection → ↑ transmission
small amount of individuals do not have cell receptors and do not develop AIDS
social implications: death of parents → orphans expenses in treatment → poverty unemployment discrimination/homophobia family & friends suffer grief lack of edu → unequal occurrence of HIV/AIDS gov/social/faith-based services → inequality of treatment
explain the need for a ventilation system and the mechanism of ventilation of lungs (8)
need:
most cellular respiration is aerobic → drives the need for gas exchange and oxygen
gas exchange depends upon a ventilation system
exchanges oxygen and CO2 between inhaled air and blood stream
alveoli provide surface area for gas exchange
ventilation system maintains a high concentration of oxygen in the alveoli
bloodstream links alveoli to cells
inhalation:
air enters lungs through trachea, bronchi & bronchioles
external intercostal muscles contract → ribs move upwards/outwards
diaphragm contracts → flattens
↑ vol of thorax → ↓ pressure → allow air to enter passively
exhalation:
air exits lungs through trachea, bronchi & bronchioles
external intercostal muscles relax → ribs to move downwards/inwards
abdominal muscles contract to push diaphragm up → diaphragm relaxes → returns to original domed position
↓ vol of thorax → ↑ pressure → force air out of lungs
a conc gradient of oxygen between air sacs & blood needs to be maintained
describe what happens in alveoli (4)
vol of alveoli ↑ as air enters alveoli during inhalation
network of capillaries in which blood flows through
gas exchange occurs
oxygen diffuses from air to blood: binds to haemoglobin in red blood cells
carbon dioxide diffuses from blood to air
type II pneumocytes secrete surfactant to prevent sides of alveoli adhering
outline the process of gas exchange necessary for aerobic respiration (3)
oxygen is taken up by cells
carbon dioxide is released by cells
gases pass through a cell membrane by simple diffusion
require a concentration gradient
no need ATP
red blood cell has large surface area to volume ratio
describe the structure of the ventilation system, including the alveoli (8)
ventilation occurs within the lungs trachea divides to form 2 bronchi divide to form bronchioles several divisions of bronchioles alveoli connected to bronchioles lined with cilia have c-shaped cartilage
diaphragm and intercostal muscles
alveoli
small
many alveoli → ↑ surface area → ↑ absorption rate
thin epithelial layer of 1 cell only → ↓ diffusion distance → ↑ absorption rate
surrounded by a dense network of capillaries → ↓ diffusion distance + steep conc gradient → ↑ absorption rate
surfactant on the inside of the alveolus produced by type II pneumocyte → allows oxygen to dissolve → diffusion of oxygen down conc gradient
draw a labelled diagram to show the human ventilation system (4)
google docs trachea bronchi bronchioles lungs alveoli: enlarged as inset diaphragm intercostal muscles abdominal (wall) muscles
