Animal Responses

Question 1

State the difference between the central nervous system and peripheral nervous system

Answer 1

CNS is the brain and spinal cord
PNS is all other neurones

Question 2

What is the role of the somatic nervous system?

Answer 2

• Conscious control of actions
• i.e. voluntary responses
• e.g. throwing a ball, walking
• Carries nerve impulses to skeletal muscles

Question 3

What is the role of the autonomic nervous system?

Answer 3

• Subconscious control
• i.e. involuntary reactions
• e.g. pupil dilation, heart beat, food digestion
• Carries nerve impulses to glands, smooth muscle or cardiac muscles

Question 4

Why are autonomic responses necessary?

Answer 4

• Frees up conscious areas of brain
• Allows multiple vital tasks to be performed without thinking

Question 5

Why can many autonomic functions also be controlled consciously?

Answer 5

• Enables response to certain situations / environments
• e.g. breathing can be controlled
• A person can hold their breath underwater
• Because not possible to breathe normally in this environment

Question 6

Outline the role of the cerebrum

Answer 6

Controls voluntary actions
- e.g. learning, memory, conscious thought, walking

Question 7

Outline the role of the cerebellum

Answer 7

Controls unconscious functions
- e.g. posture, balance, non-voluntary movement

Question 8

Outline the role of the Medulla oblongata

Answer 8

Autonomic control
- e.g. heart rate, breathing rate

Question 9

Outline the role of the hypothalamus

Answer 9

Regulatory centre for temperature (thermoregulation) and water balance (osmoregulation)

Question 10

Outline the role of pituitary gland

Answer 10

• Anterior pituitary produces hormones
• e.g. FSH
• Posterior pituitary stores and releases hormones produced by hypothalamus
• e.g. ADH

Question 11

Which part of the brain is responsible for the coordination of the autonomic control of heart rate?

Answer 11

Medulla oblongata

Question 12

Which part of the brain is responsible for osmoregulation by the kidney?

Answer 12

Hypothalamus and pituitary gland

Question 13

Which part of the brain is responsible for the coordination of the muscles involved in walking in an adult?

Answer 13

Cerebrum (conscious muscle movement) and cerebellum (balance and coordination)

Question 14

A stroke is when cells in part of the brain die. Explain how the following effects of a stroke are
caused:
- Problems with coordination of movement
- Loss of memory and speech
- Paralysis of the body below the neck

Answer 14

Problems with coordination of movement
- Damage to cerebellum

Loss of memory and speech
- Damage to cerebrum

Paralysis of the body below the neck
- Damage to medulla oblongata and/or cerebrum

Question 15

What type of actions are not processed by the brain?

Answer 15

Reflex actions

Question 16

Describe the pathway of a reflex arc

Answer 16

Receptor → Sensory neurone → Relay neurone → Motor neurone → Effector

Question 17

Describe the actions that take place when you touch a sharp object

Answer 17

• Pressure receptors in skin detect change in pressure
• Sensory neurone passes nerve impulses to spinal cord
• Relay neurone passes impulses across the spinal cord
• Motor neurone passes impulses to the effector (a muscle)
• Muscle contracts
• Body part is removed from sharp object

Question 18

What is the purpose of the knee-jerk reflex?

Answer 18

Helps body maintain posture and balance

Question 19

What does the absence of a knee-jerk reflex indicate?

Answer 19

Nerve damage in spinal cord

Question 20

What type of reflex in the blinking reflex?

Answer 20

Cranial reflex
- Occurs in brain
- Involuntary response

Question 21

What is the purpose of the blinking reflex?

Answer 21

Prevents objects entering or damaging eye

Question 22

Explain how the blinking reflex occurs

Answer 22

• Cornea of eye irritated
• Stimulus triggers impulse along sensory neurone
• Impulses passes along relay neurone in lower brain stem
• Impulses sent along motor neurone to muscles in eyelids
• Causes eyelids to close

Question 23

Explain how a reflex action can improve an organism’s chance of survival

Answer 23

Reflex arc does not include the brain
- Involuntary response
- Prevents brain being overloaded
Decreases time taken for body to react to harmful situation
Does not have to be learnt
- Provides immediate protection

Question 24

Define coordinated response

Answer 24

• Nervous and endocrine systems working together
• Detect and respond appropriately to stimuli

Question 25

Describe the fight or flight response

Answer 25

• Coordinated response in mammals
• Body reacts to potentially dangerous situations
• Prepares body to either run or fight

Question 26

Which part of the nervous system detects potential threats?

Answer 26

Autonomic nervous system

Question 27

Which part of the nervous system is stimulated in the fight or flight response?

Answer 27

Sympathetic nervous system

Question 28

Which hormones are involved in the fight or flight response?

Answer 28

• Adrenaline
• Noradrenaline

Question 29

Explain the effect of adrenaline on liver cells

Answer 29

• Triggers increase in glycogenolysis
• Makes more glucose available for respiration

Question 30

Where are adrenaline and noradrenaline secreted from?

Answer 30

Adrenal medulla

Question 31

Why can’t adrenaline cross plasma membranes?

Answer 31

Hydrophilic molecule
- Not lipid soluble