senses

Question 1

What is the difference between rods and cones

Answer 1

Rods : noncolor vision, high sensitivity they function in dim light, Low acuity, more numerous, mostly peripheral retina. Cones : colour vision, low sensitivity they function in bright light, high acuity, less numerous and mostly in the central retina

Question 2

Define transduction

Answer 2

1. Stimulus energy: A stimulus (like light, sound, or touch) activates a receptor.
2. Receptor potential: This activation changes the receptor cell’s electrical state.
3. Neurotransmitter release: The change causes the receptor cell to release chemicals called neurotransmitters.
4. Action potential: These neurotransmitters trigger an electrical signal (action potential) in a nearby nerve cell.
5. Signal to brain: The electrical signal travels to the brain, where it is interpreted.

Question 3

How do we hear sound?

Answer 3

Sound waves travel through the ear canal, they then hit the ear drum and make it vibrate, tiny bones in the middle ear ( auditory ossicles) pick up and amplify these vibrations, then pass them to the oval window, Vibrations then move fluid inside the cochlea. Hair cells in the cochlea detect these fluid movements, hair cells then send signals through the cochlear nerve, finally Signals travel via cranial nerve VIII to the midbrain, then to the thalamus, and finally to the primary auditory cortex in the temporal lobe where the sound is processed and interpreted.

Question 4

Name the three layers of the eye and their functions. What are some specific landmarks on the retina

Answer 4

1. Fibrous layer : > Sclera : white connective tissue
   > Cornea : avascular can be transplanted without rejection, lots of nerve ending, low H20 content, regenerates all the time, important for vision as light travels through here first
2. Vascular Layer =
   >Choroid : lots of blood vessels and pigment
   > Ciliary body and iris
3. Inner layer = retina :  Pigmented layer : next to choroid
    Neural layer – rods and cones, macula lutea with fovea centralis

Question 5

What is an osteon?

Answer 5

An osteon, also known as a Haversian system, is the fundamental structural unit of compact bone.
1. Central Canal (Haversian Canal) : A central channel that contains blood vessels and nerves.
2. Lamellae: Concentric rings of bone matrix surrounding the central canal, providing strength.
3. Lacunae: Small spaces between the lamellae that house osteocytes (bone cells).
4. Canaliculi: Tiny channels connecting lacunae, allowing for nutrient and waste exchange between osteocytes and the central canal.
5. Osteocytes: Mature bone cells located in the lacunae that maintain the bone matrix.

Question 6

What are the movements in the hip joint in the frontal planes?

Answer 6

Abduction – moving the leg away from the midline of the body & Adduction – moving the leg toward the midline of the body

Question 7

What are the movements in the hip joint in the sagittal planes?

Answer 7

Flexion – brining the thigh forward and upward (like lifting your knee) & Extension – brining the thigh backwards

Question 8

What are the movements in the hip joint in the transverse planes?

Answer 8

Medial (internal) rotation – rotating the thigh inwards, towards the midline of the body , Lateral (external) Rotation – rotating the thigh outwards, away from the midline of the body, Horizontal abduction – moving the thigh away from the midline while the hip is flexed at a 90 degree angle, Horizontal adduction – moving the thigh towards the midline while the hip is flexed at a 90 degree angle

Question 9

What are the specific movements in the elbow joint

Answer 9

Flexion : bending the elbow to decrease the angle between the forearm and the upper arm (bringing the hand closer to the shoulder) & Extension : straightening the elbow to increase the angle between the forearm the upper arm (bringing the hand closer to the shoulder)

Question 10

What are the specific movements in the ankle joint

Answer 10

Dorsiflexion : lifting the foot upwards towards the shin, Plantarflexion : pointing the foot downward away from the shin, Inversion : Tilting the sole of the foot inward toward the midline of the body and Eversion: Tilting the sole of the foot outward away from the midline of the body.

Question 11

What are the two main parts of the skeleton?

Answer 11

1. Axial Skeleton: The central part of the skeleton.
   
   • Skull: Protects the brain and forms the face.
   • Spine: Protects the spinal cord and supports the body.
   • Rib Cage: Protects the heart and lungs
   • Sternum: The breastbone in the rib cage.
2. Appendicular Skeleton: The bones of the limbs and the girdles that connect them to the axial skeleton.
   
   • Shoulder Girdle: Includes the collarbones and shoulder blades.
   • Arms: Includes the upper arm, forearm, and hand bones.
   • Pelvic Girdle: Includes the hip bones.
   • Legs: Includes the thigh, lower leg, and foot bones.

Question 12

What are the four layers of the alimentary canal?

Answer 12

1. Mucosa
2. Submucosa
3. Muscularis externa
4. serosa

Question 13

explain mucosa

Answer 13

Simple columnar epithelium, loose areolar connective tissue and smooth tissues. The mucosa secretes mucus, enzymes and hormones, it protects underlying layers, absorbs digested end products

Question 14

Explain submucosa

Answer 14

areolar connective tissue, submucosa contains blood vessels, nerves and elastic fibres and maintains the shapes of organs

Question 15

explain muscularis externa

Answer 15

smooth muscles, longitudinal and circular layers, it contributes to motility in the alimentary Canal

Question 16

explain serosa

Answer 16

visceral peritoneum, protects and holds organs in place

Question 17

What are the 6 processes and steps from eating to defaecating?

Answer 17

1. Ingestion = eating
2. Propulsion = the movement of food through the alimentary canal, via swallowing and peristalsis
3. Mechanical breakdown = chewing, mixing food with saliva, churning food in stomach and segmentation
4. Digestion = senses of catabolic steps that involve enzymes that break down complex food molecules into chemical building blocks
5. Absorption = passage of digested fragments from lumen of GI tract into blood or lymph
6. Defecation = elimination of indigestible substances via anus in form of faeces

Question 18

Name some organs that are intra- and some that are retro-peritoneal.

Answer 18

Intra : stomach, jejunum, ileum, caecum, appendix, transverse colon, sigmoid, liver, pancreatic tail, top 1/3 of rectum
Retro : duodenum, pancreas, ascending and descending colon, kidneys, pancreatic hair, middle 1/3 of rectum

Question 19

How are gut bacteria important?

Answer 19

Metabolic functions – Ferment indigestible carbohydrates into fatty acids, synthesize B complex and some vitamin K
Keeping pathogenic bacteria in check
Support health – Body weight, susceptibility to various diseases (including diabetes, atherosclerosis, fatty liver disease), mental health

Question 20

How does the stomach protect itself from acid?

Answer 20

Muccous cells produce a viscous, alkaline mucous (contains bicarbonate)
Prostaglandin stimulates alkaline mucous production
Tightly joined cells that regenerate all the time
Good blood supply
Regulation of HCl production in parietal cells (also make intrinsic factor) via reflexes

Question 21

cortex function - kidney

Answer 21

Granular appearance due to all the renal corpuscles being located here. they do all the filtration of the blood. Also contains the start and end points of the renal tubules

Question 22

medulla function - kidney

Answer 22

is made up of lobes, which contains a pyramid and columns (extensions from the cortex). Pyramids are made up of renal tubules and capillaries

Question 23

pelvis function - kidney

Answer 23

a funnel shaped tube, collects the urine from the renal tubules, leading into the ureter

Question 24

column function - kidney

Answer 24

extensions of the cortex into the medulla, also contain renal corpuscles and proximal and distal convoluted tubules

Question 25

Pyramid function - kidney

Answer 25

Made up of the renal tubules and capillaries that are arranged in parallel bundles. Here reabsorption and secretion occurs. The inward pointing tip is called papilla

Question 26

Calyx (minor and major) function - kidney

Answer 26

These are extensions of the renal pelvis, collecting urine from the collecting ducts first into the minor, then into the major calyces

Question 27

hilum function - kidney

Answer 27

exit point of the ureter and the renal vein, entry point of the renal artery

Question 28

ureter function - kidney

Answer 28

transporting the collected urine to the bladder

Question 29

renal vein and artery function - kidney

Answer 29

bringing blood to the kidneys for filtration, reabsorption and secretion, also supplies oxygenated blood to the kidney itself to enable it to do its work. processed blood then enters the renal vein and then vena cava

Question 30

what are the kidneys 3 processes

Answer 30

* Filtration = happens in the glomerulus * Reabsorption = 99% of substances get returned to the blood in the tubules (mainly PCT) * Secretion = happens in both the tubules (mainly DCT) and the collecting ducts

Question 31

which hormones act on the nephron and what are their effects

Answer 31

Antidiuretic hormone (ADH) : decreases urine output by increasing water absorption, makes collecting ducts more permeable Aldosterone : increases Na+ reabsorption and water follows, so increases blood volume/pressure Atrial natriuretic peptide (ANP) - inhibits Na+ reabsorption, so decreases blood volume/pressure

Question 32

What symptoms will you see if a person has chronic kidney failure and what is the underlying cause?

Answer 32

* Peripheral oedema – Leakage of proteins across damaged filtration membranes causes fluid shifts from the blood vessels into the surrounding tissues, leading to oedema. * Skin has yellow tinge, dry and itchy – accumulating waste products, such as urea cause these skin changes. * Muscle cramping – due to hypocalcaemia (insufficient Ca2+ levels as not enough is reabsorbed), also insufficient Vit. D activation prevents uptake of Ca2+ from food. * Fatigue – Hyperkalaemia (insufficient secretion of too much K+ leads to muscle weakness; damaged kidneys also don’t produce sufficient erythropoietin (responsible for red blood cell formation), so the patient becomes anaemic, which causes fatigue (not enough oxygen available). * Weight loss and low appetite – caused by the general electrolyte imbalances and feeling very unwell.

Question 33

Neutrophil characteristics and function

Answer 33

characteristics = granulocyte, multilobed nucleus, most common WBC. Function = phagocyte, target bacteria

Question 34

Eosinophil characteristics and function

Answer 34

Charcteristics are granulocyte, bilobed nucleus, red appearance, low numbers. Its function is to kill parasites

Question 35

Basophil characteristics and functions

Answer 35

characteristics - granulocyte, bilobed nucleus, purple appearance, lowest number of all wbc, function = releases histamine

Question 36

lymphocyte characteristics and function

Answer 36

characteristics : agranulocyte, small cell with very large nucleus, b & T cells, second most common WBC. Function : specific immune response via antibodies (b plasma cells) or direct attack of infected cells (T cells)

Question 37

monocyte characteristics and function

Answer 37

characteristics : agranulocyte, small cell with very large nucleus, b and T cells and second most common WBC. function : phagocytes, develop into macrophages when migrating into tissues

Question 38

how does the body distinguish between self and foreign or faulty?

Answer 38

* Cell surface proteins (glycoproteins) * May present “self” (self-tolerance) or “foreign” antigen * Helps immune system to detect “foreign“ * Class I – all cells apart from RBCs * Class II – APCs, B-cells

Question 39

How do the nervous and endocrine system differ?

Answer 39

endocrine : initiates responses slowly, long duration responses, acts via diffuse locations, hormones act over long distance Nervous system : initiates responses rapidly, short duration responses, acts via action potentials and neurotransmitters, acts a specific locations determined by axon pathway and neurotransmitters act over very short distances

Question 40

How do hormones get regulated?

Answer 40

> Release has patterns – diurnal, cyclic > Hormones are regulated by chemical (humoral), endocrine or neural factors > Negative and positive feedback cycles > Up and down regulation > Half-life = hormone’s blood level decreased to half of the original concentration that was released from the gland

Question 41

Name three hormones of the anterior pituitary gland and their effects.

Answer 41

1. Humoral Stimulus – hormone release caused by altered levels of certain critical ions or nutrients 2. Neural Stimulus - Hormone release caused by neural input 3. Hormonal Stimulus – Hormone release caused by another hormone (a tropic hormone)

Question 42

How is blood glucose level maintained? Which hormones are involved?

Answer 42

* Pancreas produces hormones in Islets of Langerhans * Insulin > Produced and secreted by beta cells >Secretion is promoted by hyperglycaemia > Glucose uptake into the cells of the body > Synthesis of glycogen (in liver/muscles) and conversion into fat (in adipose tissue) * Glucagon > Produced and secreted by alpha cells > Secretion is promoted by hypoglycaemia > Stimulates breakdown of glycogen, fat and muscle tissue to make glucose out of fatty acids and protein

Question 43

Describe the characteristics of sperm and how it gets to the oocyte for fertilization.

Answer 43

> Sperm is produced in large numbers, > Have a tail for movement, > Have enzymes in the acrosome to digest the ovum lining before entry > Receive nourishment from fluids of the accessory glands > Are surrounded by that alkaline fluid to be protected from acidic environment in vagina > Travel from testis, epididymis, ductus deferens, male urethra, vagina, cervix, uterus, uterine tube > Needs to undergo capacitation = motility must be enhanced, and cell membranes must become fragile enough to release hydrolytic enzymes before it can penetrate oocyte

Question 44

Describe how the oocyte travels towards the sperm. Include the process of ovulation.

Answer 44

> Primary and secondary > Has follicle around it which matures under the influence of hormones (FSH, oestrogen) > Ovulation is the rupturing of the vesicular follicle and the release of the secondary oocyte into the peritoneal cavity approximately on day 14 of the ovarian cycle and is triggered by a surge in LH. > Fimbriae need to catch and guide it into uterine tube. Tubes contract and move egg along. > Once one sperm enters, fertilisation has occurred and oocyte becomes zygote (egg). Nuclei fuse and zygote has genetic material from both father and mother.