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A level biology > M5 CH13 > Flashcards

M5 CH13 Flashcards

1
Q

state where the cerebrum is found in the brain, and outline its main functions (3)

A
  • top of the head
  • voluntary actions: learning, memory, personality
  • sends impulses along neurones to effectors
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2
Q

explain how the cerebrum is divided, and how it receives impulses (3)

A
  • divided into left and right hemisphere
  • left hemisphere receives impulses from the right hand side of the body
  • right hemisphere receives impulses from the left hand side of the body
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3
Q

state where the cerebellum is found in the brain, and outline its functions (3)

A
  • found @ back of head (looks like a leaf !!)
  • unconcious functions: posture, balance, non voluntary movement
  • relays information to the cerebral cortex involved in motor control
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4
Q

state where the medulla oblongata is found in the brain, and outline its functions (3)

A
  • found in centre of head, low down (near where neck and head meet)
  • autonomic control: controls breathing rate and heart rate
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5
Q

state where the hypothalamus is found in the brain, and outline its functions. (4)

A
  • very centre of brain: above medulla
  • regulatory centre for temperature and water balance
  • controls behaviour patterns: aggression, sleeping
  • produces hormones
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6
Q

state where the pituitary gland is found, and outline its functions.

A
  • centre towards front of brain, in line with tip of nose, before hypothalamus
  • stores and releases hormones
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7
Q

distinguish the anterior and posterior pituitary glands

A

anterior: produces hormones, e.g. FSH

posterior: stores and releases hormones, e.g. ADH

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8
Q

outline the 6 steps of a reflex arc

A
  1. stimulus
  2. receptor (creates A.P)
  3. sensory neurone (carries impulse to spinal cord)
  4. relay neurone (connects sensory and motor neurone)
  5. motor neurone (carries impulse to effector
  6. effector muscle contracts
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9
Q

state what type of reflex the knee jerk reflex is, and how it works

A
  • spinal reflex
  • leg is hit with hammer, stretching patella tendon
  • causes extensor muscle on top to contract
  • flexor muscle underneath relaxes
  • causes leg to kick
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10
Q

state what could be concluded from the absense of a knee jerking reflex

A

potential cerebellar disease

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11
Q

outline the characteristics and functioning of the blinking reflex

A
  • occurs in brain
  • occurs when cornea is stimulated
  • cornea is stimulated by being touched by something (e.g. foreign particle)
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12
Q

explain what an optical reflex is

A

type of blinking reflex
in response to light

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13
Q

outline the importance of reflexes in survival (4)

A
  • extremely fast
  • present from birth
  • involuntary; happen straight away
  • used in everyday functioning; e.g. not falling over
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14
Q

sensory receptors are transducers; explain the meaning of a transducer

A

they convert stimuli into electrical impulses

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15
Q

explain what a mechanoreceptor is, and give an example

A

sensory receptor that detects changes in pressure; pacinian corpuscle

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16
Q

outline the characteristics of a pacinian corpuscle (3)

A

connective tissue with gel inbetween
tissue contains stretch mediated sodium channels
special channel proteins in plasma membrane

17
Q

explain the steps in which a pacinian corpuscle creates an action potential (5)

A
  1. pressure applied to PC
  2. causes stretch m sodium channels to open
  3. sodium ions diffuse into axon
  4. influx of na depolarises membrane (more + inside now)
  5. causes a generator potential, which triggers an action potential
18
Q

explain the meaning of saltatory conduction

A

the action potential jumps from node to node (of ranvier) along neurone
means the AP travels faster

19
Q

outline the features and function of sensory neurones (3)

A

long dendron and axon
myelinated
carries impulses from sensory receptors to next neurone (usually relay neurone)

20
Q

outline the features and role of relay neurones (3)

A

short axons and dendrons
NON myelinated
carry impulse from sensory neurones to motor neurones

21
Q

outline the features and role of motor neurones. (3)

A

long axon and short dendrons
myelinated
carry impulse from relay neurones to EFFECTORS

22
Q

outline the mechanism of the sodium potassium pump

A

pumps 3 sodium out, 2 potassium IN

23
Q

explain how an action potential is generated in a pacinian corpuscle (6)

A
  1. pressure applied to PC
  2. stretch mediated sodium channels are opened
  3. causes influx of sodium ions
  4. membrane is depolarised
  5. causes generator potential
  6. GP creates action potential
24
Q

explain how a resting potential is created, starting with the sodium potassium pump

A

1; due to na/k pump, more sodium outside of axon (more k inside)
2; k ion channels are open so k ions are diffusing out, more na outside causes sodium ions to diffuse back in down electrochemical gradient
3; na vg gated channels are closed so movement of sodium in is limited
4; therefore, the outside is moer + charged due to more ions outside- creates RP of -70mv

A level biology (19 decks)

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