excretion; co-ordination and response Flashcards

1
Q

what are the kidneys main roles

A

1) remove urea
2) adjust ion levels in blood
3) adjust the water content in blood

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2
Q

describe the structure of the urinary system

A

renal vein and renal artery connect to kidney; ureter joins kidney with bladder; sphincter muscle then urethra.

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3
Q

describe the structure of a nephron

A

glomerulus; bowmans capsule; proximal convoluted tubule; loop of henle; distal convoluted tubule; collecting duct.

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4
Q

describe ultrafiltration in the Bowman’s capsule

A

1) blood from the renal artery flows through the glomerulus (a bundle of capillaries at the start of the nephron
2) a high pressure is built up which squeezes water, urea, ions and glucose out of the blood.
3) the basement membrane is like a filter so stops big molecules like protein and blood cells from being squeezed out

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5
Q

what makes up the glomerular filtrate

A

urea, water, glucose, ions.

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6
Q

why is glucose reabsorbed in the proximal convoluted tubule

A

glucose is needed for respiration so it is absorbed by active transport.

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7
Q

describe the role of ADH in regulating the water content of the blood

A

1) water loss
2) brain detects water loss
3) pituitary gland releases more ADH
4) ADH makes the collecting ducts of the nephrons MORE permeable so more water is reabsorbed into blood
(same in reverse for water gain).

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8
Q

define homeostasis

A

the maintenance of a constant internal environment.

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9
Q

what does a co-ordinated response require

A

stimulus, receptor, effector

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10
Q

what is the role of auxin in the phototrophic response of stems

A

when a shoot is exposed to light, the auxin goes to the dark side. auxin makes the shaded side grow faster so the plant bends towards the light

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11
Q

what are the differences between the nervous and endocrine systems

A

1) Nerves= very fast messages; hormones = slower messages
2) nerves act for a very short time; hormones for longer
3) nerves act on a very precise area; hormones act in a more general way

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12
Q

what is the central nervous system

A

the brain and the spine (it is linked to sense organs by nerves

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13
Q

describe how responses to stimuli happen

A

1) the receptors detect stimuli
2) the sense organ sends electrical impulses along nerves in and out of the central nervous system
3) the effector brings about a response

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14
Q

what is the role of neurotransmitters at synapses

A

the neurotransmitter transfers the nerve signal by diffusing across the gap and then setting off a new electric signal in the next neurone

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15
Q

describe a simple reflex arc

A
  • stimulus (eg hot object) detected by receptor; impulse sent along a sensory neurone to the CNS.
  • the sensory neurone passes the message to the relay neurone . -the relay neurone relays the impulse to a motor neurone.
  • the impulse travels along the motor neurone to the effector
  • the muscle contracts and pulls hand away from the candle
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16
Q

describe the structure and function of the eye as a receptor

A

1) cornea refracts light into the eye
2) iris controls the diameter of the pupil
4) the lens focuses the light on the retina
5) the optic nerve carries impulses from the receptors to the brain

17
Q

describe the iris reflex

A

1) bright light: circular muscles contract, radial muscles relax. Pupil gets smaller
2) dim light: circular muscles relax, radial muscles contract. Pupil gets bigger

18
Q

explain how the eye focuses on near and distant objects

A

1) near:
ciliary muscles contract, suspensory ligaments slacken.
the lens gets more rounded to refract light more
2) distant:
ciliary muscles relax, suspensory ligaments tighten.
the lens gets more flat to refract light less

19
Q

describe the role of the skin in temperature regulation

A

1) sweating: water evaporates, transferring energy from the body to the environment
2) vasodilation: blood vessels close to the surface widen, allowing more blood to flow near the surface, so more heat is lost to surroundings
3) vasoconstriction: opposite of vasodilation
4) hair erector muscles: contract making hairs stand up; traps an insulating layer of air.

20
Q

what is the source, role and effect of adrenaline

A

source: adrenal glands
role: readies the body for flight or fight response
effect: increases heart rate, blood flow and blood sugar level

21
Q

what is the source, role and effect of insulin

A

source: pancreas
role: control blood sugar level
effect: stimulates liver to turn glucose into glycogen

22
Q

what is the source, role and effect of testosterone

A

source: testes
role: main male sex hormone
effect: promotes male secondary sex characteristics

23
Q

what is the source, role and effect of progesterone

A

source: ovaries
role: supports pregnancy
effect: maintains lining of uterus

24
Q

what is the source, role and effect of oestrogen

A

source: ovaries
role: main female sex hormone
effect: controls the menstrual cycle + promotes female secondary characteristics

25
Q

ADH

A

source: pituitary gland
role: controls water content
effect: increases the permeability of the kidney tubules to water

26
Q

FSH

A

source: pituitary gland
role: female sex hormone
effect: causes an egg to mature in the ovary + stimulates the ovaries to produce oestrogen

27
Q

LH

A

source: pituitary gland
role: female sex hormone
effect: stimulates the release of an egg from an ovary

28
Q

insulin

A

source: pancreas
role: control blood sugar levels
effect: stimulates the liver to convert glucose to insoluble glycogen, lowering blood sugar levels

29
Q

glucagon

A

source: pancreas
role: control blood sugar levels
effect: stimulates the liver to convert insoluble glycogen to glucose, raising blood sugar levels

30
Q

conjunctivia

A

lubricates and protects the eyes surface

31
Q

sclera

A

the tough outer layer that protects the eye

32
Q

cornea

A

refracts light into the eye. The cornea is transparent and has no blood vessels so oxygen diffuses in and out from the outer surface

33
Q

iris

A

controls the diameter of the pupil and therefore how much light enters the eye

34
Q

lens

A

focuses the light onto the retina

35
Q

retina

A

light sensitive part covered in light receptors (rods-sensitive to to light and cones-sensitive to colour)

36
Q

fovea

A

highest concentration of cone cells

37
Q

optic nerve

A

carries impulses from receptors to the brain