non-infectious diseases and disorders

Question 1

What are the components of a negative feedback loop?

Answer 1

1. Stimulus: change that occurs
2. Receptor: detects change
3. Control centre: receives info from receptor
4. Effectors: muscles, organs, glands
5. Response: what the effector does to counteract stimulus

Question 2

name behavioural adaptations.
give at least 2

Answer 2

• move to shaded/exposed areas to decrease/increase heat exposure
• move to different habitats that are within their tolerance range
• increasing SA available for heat absorption
• enabling more heat to be evaporated through saliva on itself
• replenish fluids –> maintain cells in a consistent, isotonic state
• remain inactive during the heat of the day to prevent increased metabolic body heat

Question 3

name structural adaptations.
give at least 2

Answer 3

• feathers, hair, fur trap provides insulation –> reduces amount of heat lost
• compact bodies reduces SA available for heat exchange –> animals to retain heat more effectively + vice versa

Question 4

name physiological adaptations.
give at least 2

Answer 4

• vasoconstricting/dilating –> alters amount of heat lost to surroundings
• increased/decreased metabolism –> produce heat energy internally/cool body temperature
• making small muscular contractions produces heat energy
• sweat evaporates from the skin –> cooling effect

Question 5

what does the central nervous system consist of?

Answer 5

brain and spinal cord

Question 6

what does the peripheral nervous system consist of?

Answer 6

all nerves throughout body that aren’t brain and spinal cord

Question 7

what does the peripheral nervous system do?

Answer 7

detects+carries information to and from central nervous system via electrochemical responses

Question 8

describe the 4 main parts of the neuron.

Answer 8

• cell body: contains nucleus, organelles while maintaining cell function
• dendrites: branch-like extensions that receive signals –> conveys them toward the cell body
• axon: long extensions of the cytoplasm that conduct messages away from the cell body
• myelin sheath: fatty insulating substance protects some nerve fibres

Question 9

what’s the function and general structure of motor neurons, interneurons, sensory neurons, respectively.

Answer 9

• transfer messages from CNS to effectors (muscles/glands) - Short dendrite, long axon.
• the link between sensory and motor neurons (found in CNS) - Short dendrite, short axon.
• carry impulses from sensory cells in the PNS to CNS - Long dendrite, short axon.

Question 10

describe how plants maintain water balance.
give at least 2 specific examples

Answer 10

• high water level is in plants –> guard cells on leaves absorb water –> turgid –> thin outer walls to stretch outwards, while the thick inner walls don’t bulge –> stomata opens –> water diffused out of the plant until homeostasis
• low water level –> guard cells become flaccid + stomata close –> reduces water loss
  Orientation: angling leaves away from the sun at different times of the day reduces
  the rate of transpiration
• Smaller leaves - smaller SA:V
• Water storage
• Regulating the opening and closing of stomata
• Waxy cuticle - waterproof

Question 11

what are the different components of the ear?

Answer 11

Pina, outer ear canal, ear drum, ossicles, oval window, round window, cochlear, auditory nerve

Question 12

what’s the function of the pina?

Answer 12

Collects sound waves from the external environment and directs it into the outer ear canal.

Question 13

what’s the function of the outer ear canal?

Answer 13

Carries sound waves to the eardrum

Question 14

what’s the function of the eardrum?

Answer 14

Vibrates due to sound waves and transmits these vibrations to the middle ear

Question 15

what’s the function of the ossicles?

Answer 15

Amplify vibrations from the ear drum and transfer these to the oval window via the stirrup

Question 16

what’s the function of the oval window?

Answer 16

Separates the middle ear from the fluid-filled cochlea.

Question 17

what’s the function of the round window?

Answer 17

Vibrates in conjunction with the oval window, allowing the fluid in the cochlea to move

Question 18

what’s the function of the cochlea?

Answer 18

Contains fluid. Organ of corti in the cochlea picks up the sound waves and converts the vibrations into chemical impulses

Question 19

what’s the function of the auditory nerve?

Answer 19

Carries the electrochemical impulses from the receptor cells in the cochlea to the brain

Question 20

what are the two types of hearing loss and where do they occur?

Answer 20

conductive: outermiddle ear
sensorineural: inner ear

Question 21

what are the factors of conductive hearing loss?

Answer 21

• problem with mechanical conduction of vibrations through the
  outer/middle ear.
  
  • cochlea may still be functional but receives insufficient signal to create an auditory impulse.
• inhibits movement of vibrations
  through the outer and middle ear.
• due to structural malformation, perforated eardrum, outer/middle ear infection, damaged ossicles from trauma (sudden loud noises) or hardening of stirrup.

Question 22

what are the factors of sensorineural hearing loss?

Answer 22

• damage to/malformation of inner ear (incl. parts of cochlea, hair cells, auditory nerve)
• damage and hearing loss usually permanent –> decreased loudness and clarity of sound.
• excessive noise exposure, heredity, birth defects, infections, tumours, medication, ageing

Question 23

What’s the characteristics+function of the sclera?

Answer 23

Opaque, tough protective coat that surrounds the eyes.

Question 24

What’s the characteristics+function of the cornea?

Answer 24

Transparent structure of the sclera that covers the iris and pupil and allows light to enter the eye

Question 25

What's the characteristics+function of the aqueous humour?

Answer 25

Clear fluid between the cornea and the lens of the eye

Question 26

What's the characteristics+function of the pupil?

Answer 26

Hole in the centre of the iris where light enters the eye.

Question 27

What's the characteristics+function of the iris?

Answer 27

- Ring of muscle - Forms coloured part of the eye - Controls how wide the pupil is+how much light passes through the eye - Bright light --> iris narrows the pupil --> reducing amount of light entering the eye + vice versa

Question 28

What's the characteristics+function of the lens?

Answer 28

Biconvex, elastic structure that changes shape to refract light via accommodation

Question 29

What's the characteristics+function of the vitreous humour?

Answer 29

Clear fluid between the lens and the retina which reflects light, helps maintain the shape of the eyeball

Question 30

What's the characteristics+function of the retina?

Answer 30

Thin membrane lined photoreceptors covering the rear portion of the eye.

Question 31

What's the characteristics+function of the fovea?

Answer 31

Depression in the macula, centre of the retina, contains cones and provides the greatest visual acuity

Question 32

What's the characteristics+function of the optic nerve?

Answer 32

Carries the electrochemical impulses from the rod and cone cells in the retina to the brain.

Question 33

what are the components of the eye?

Answer 33

sclera, cornea, aqueous humour, pupil, iris, lens, vitreous humour, retina, fovea, optic nerve

Question 34

purpose of cone and rod cells

Answer 34

- conversion into electrochemical impulses --> brain for interpretation as images - photosensitive pigments - retinal, a molecule derived from vitamin A+opsin. - when exposed to light --> retinal molecule changes its form --> light energy electrochemical impulses.

Question 35

compare cone cells and rod cells distribution, structure, function.

Answer 35

rod: evenly distributed, mostly in periphery, absent from fovea, rhodopsin(can't detect colour), sensitive to low levels of light, night vision, detects light, shadow, contrasts and movement, peripheral vision cone: in groups, middle of retina, concentrated in fovea, iodopsin, sensitive to red, green, blue, colour vision but relies on stimulation of opsin by visible light

Question 36

whats a common visual disorders?

Answer 36

myopia and hyperopia, macular degeneration, cataracts

Question 37

what are the 3 main functions of the kidney?

Answer 37

- filtering small substance out through glomerulus walls, large molecules stay in capillaries - reabsorption of substances required by the body from tubules of kidney to capillaries by diffusion or active transport - excreting toxic substances such as urea and creatine from blood capillaries into the urine in the renal tubules of the nephron

Question 38

what are the components of the kidneys?

Answer 38

renal arteries, nephron, glomerulus, bowman's capsule, proximal tube, loop of henle, distal tube, collecting duct

Question 39

what's the function of the renal arteries?

Answer 39

Carries blood from the heart to the kidney.

Question 40

what's the function of the nephron?

Answer 40

Removes urea and balances salt and water levels in the blood.

Question 41

what's the function of the glomerulus?

Answer 41

Network of capillaries inside the Bowman’s capsule.

Question 42

what's the function of the bowman's capsule?

Answer 42

Hollow structure in the nephron that receives filtrate from the glomerulus and allows it to pass into the tubules.

Question 43

what's the function of the proximal tube?

Answer 43

Tubule closest to the Bowman’s capsule and reabsorbs required substances into the bloodstream

Question 44

what's the function of the loop of henle?

Answer 44

Part of the tubule that is in the medulla and plays a role in osmoregulation

Question 45

what's the function of the distal tube?

Answer 45

Tubule further away from the Bowman’s capsule and reabsorbs required substances into the bloodstream

Question 46

what's the function of the collecting duct?

Answer 46

Contains water and waste that remain after filtration, reabsorption and secretion

Question 47

What are some causes of loss of kidney function?

Answer 47

- high levels of blood glucose --> filter more blood --> stress of nephrons --> damaged - nephrons’ unable to carry out filtration --> molecules - proteins ‘leak’ into the tubules --> blockages - constant high force of the blood being pushed through the walls of the blood vessels of the glomerulus into the Bowman’s capsule permanently damages the nephrons - recurrent kidney infections --> damages nephrons

Question 48

outline how a cochlear implant works.

Answer 48

- device replaces function of the hair cells on Organ of Corti on a damaged cochlea. - microphone of the speech processors detects sound--> digital signal --> transmitter --> receiver - digital sounds to electrical signals. - signals --> electrode array implanted in cochlea, nerve endings are stimulated, signals to brain.

Question 49

outline how a bone conduction implant works.

Answer 49

- microphone in processor behind ear detects sound waves --> vibrations. - Vibrations transmitted by implants to bone above the ear --> the bone --> cochlea. - sound vibrations cause movement in fluid of cochlea --> movement of hair cells --> electrical impulse --> auditory nerve

Question 50

outline how a hearing aid works.

Answer 50

- worn in or behind ear to magnify vibrations --> better transmission from mid ear to inner ear - magnifying sound vibrations that enter ear --> increased hearing sensitivity

Question 51

how does laser eye surgery work?

Answer 51

- lasers change curvature of cornea --> light correctly refracted --> focused image on the retina. - surgeon creates thin flap, top of the cornea, folded back to access underlying stroma . - excimer laser uses short-wave ultraviolet light removes tiny amounts of tissue to reshape the cornea --> focuses more accurately. - myopia --> cornea is flattened hyperopia --> curvature of the cornea is increased.

Question 52

how do spectacles work for hyperopia and myopia?

Answer 52

- concave lenses are thicker towards the outside and thinner towards the inside --> myopia. - lenses bend the light rays outwards causing them to diverge before reaching the eye. - extends focal length of light rays --> focused distant image fall on retina instead of in front - convex lenses are thicker toward the centre and thinner towards the edges --> hyperopia. - lens bends incoming light rays inwards, converges before they reach the eye. - shortens the focal length, focused image of a near object to fall on the retina rather than behind it

Question 53

how does haemodialysis work?

Answer 53

- dialysis machine filters blood outside of the body - patient connected dialyser pumps blood through tubes with semi-permeable membranes that only allow small molecules, such as waste materials, to pass through. - tubes submerged in dialysate - coiled to increase SA, flows opposite direction to blood to maintain a concentration gradient --> increases diffusion rate - waste materials move through the semipermeable membrane into dialysate via diffusion as metabolic waste concentration is higher in blood than dialysate.

Question 54

how do peritoneal dialysis work?

Answer 54

- waste filtered from blood inside the body - dialysate into abdominal cavity via catheter. - lining of abdomen, peritoneum, acts as natural filtering membrane. - dialysate remains in the body for several hours, allowing high concentrations of waste materials in blood to move through peritoneum --> dialysate via diffusion. - dialysate with waste products drawn from abdomen and then discarded.