The Brain (MODULE 5)

Question 1

Structural organisation of the brain:

Answer 1

Central nervous system and peripheral nervous system

Question 2

Central nervous system (CNS):

Answer 2

Brain and spinal cord

Question 3

Peripheral nervous system (PNS):

Answer 3

All the neurones that connect the CNS to your body

Question 4

Functional organisation of the brain:

Answer 4

Somatic nervous system and autonomic nervous system

Question 5

Somatic nervous system:

Answer 5

System under conscious control/voluntary actions. The SNS carries impulses to muscles

Question 6

Autonomic nervous system:

Answer 6

System under subconscious control/automatic actions. This system works constantly, and carries impulses to glands, smooth muscle and cardiac muscle

Question 7

Example of somatic nervous system:

Answer 7

Limb movement

Question 8

Example of autonomic nervous system:

Answer 8

Heart beat and digestion of food

Question 9

Division of autonomic nervous system:

Answer 9

Sympathetic nervous system and parasympathetic

Question 10

Difference between sympathetic and parasympathetic nervous systems:

Answer 10

Sympathetic: increases general activity (increase in heart rate)
Parasympathetic: decreases general activity (decrease in heart/decrease in breathing rate)

Question 11

Gross structure of the brain:

Answer 11

Cerebrum, cerebellum, medulla oblongata, hypothalamus, pituitary gland

Question 12

Cerebrum:

Answer 12

Controls voluntary actions, such as learning, memory, personality, conscious thought

Question 13

Cerebellum:

Answer 13

Controls unconscious function such as posture, balance and non-voluntary movement. Coordinates movement

Question 14

Medulla oblongata:

Answer 14

Autonomic control, such as controlling heart and breathing rate

Question 15

Hypothalamus:

Answer 15

Thermoregulation and osmoregulation of blood plasma, producing hormone, controlling complex behaviour patterns (feeding, sleeping)

Question 16

Pituitary gland:

Answer 16

Stores and releases hormones that regulate several body functions

Question 17

Anterior pituitary:

Answer 17

Front section of pituitary gland, produces 6 hormones including LH and FSH

Question 18

Posterior pituitary:

Answer 18

Back section of the gland, stores and releases hormones produced by the hypothalamus including ADH

Question 19

Basic reflex arc:

Answer 19

Receptor -> sensory neurone -> relay neurone -> motor neurone -> effector

Question 20

Examples of reflex arcs:

Answer 20

Knee-jerk reflex (spinal reflex), blinking reflex (brain reflex)

Question 21

Knee-jerk reflex:

Answer 21

• leg is tapped below the kneecap (patella)
• stretch of patellar tendon acts as a tendon
• causes extensor muscles (top of thigh) to contract
• relay neurone inhibits the motor neurone in the flexor muscle, causing it to relax
• the SIMULTANEOUS relaxation and contraction causes the leg to kick

Question 22

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

Answer 22

Nervous problems (multiple kicks may indicate cerebellar disease)

Question 23

Purpose of the knee-jerk reflex:

Answer 23

Maintain posture and balance

Question 24

Blinking reflex:

Answer 24

• cornea stimulated
• impulse triggered along sensory neurone on the fifth cranial nerve
• impulse passes along relay neurone in the lower brain stem
• motor neurone initiates motor response to close the eyelids
• this is deemed a ‘consensual response,’ so both eyelids close

Question 25

Purpose of the blinking reflex:

Answer 25

Keep cornea safe from damage due to foreign bodies, protect lens and retina from very bright light

Question 26

What does the presence of the blinking reflex indicate?

Answer 26

Lower brain stem function

Question 27

Reflex survival importance:

Answer 27

• being involuntary responses: decision making not involved, so more energy can be used for complex responses
• not being learnt: present at birth for immediate protection
• extremely fast: short reflex arc with only one or two synapses