Physiology Of Central Nervous System

Question 1

Attribute functions to the following lobes of the cerebrum: frontal, parietal, temporal, and occipital

Answer 1

Frontal lobe

• Intelligence e.g. ability to solve complex problems and to multitask (prefrontal area)
• Voluntary motor activity e.g. ability to write.
• Speech articulation (Broca’s area)
• Moral judgement (prefrontal area)

Parietal lobes
- Sensory

Temporal lobes

• Hearing e.g. damage causes individual to hear sound that are not there
• Memory e.g. damage causes loss of long term memory
• Language and comprehension (Wernicke’s area)

Occipital lobe
- Vision

Question 2

Explain what the limbic system does and attribute specific functions to the hypothalamus, hippocampus, amygdala

Answer 2

Limbic system

• Refers to a ring of interconnected structures underneath the cortex.
• It generates emotions and motivational drives, meaning whether an experience or sensation activates a punishment or reward response.

Hypothalamus

• Neurones located in the hunger and satiety centres monitor glucose and amino acid usage to produce sensations of hunger and satiety respectively.
• Secretes hormones which control secretion by the pituitary gland and therefore helps regulate growth, metabolism, and water conservation.
• Helps to control water balance by use of osmoreceptors and antidiuretic hormone.
• The hypothalamic thermostat monitors blood temperature.
• Controls our circadian rhythm by receiving information from the optic nerve which carries information about light levels.
• Integral part of the fight or flight response.

Amygdala
- Associated with sexual behaviour including erections, ejaculation, ovulation, and uterine activity.

Hippocampus
- Important in the formation of long term memories.

Question 3

Explain what the thalamus does

Answer 3

• A mass of tissue under the cerebral hemispheres and above the midbrain.
• Almost all pathways from sensory receptors and organs go through the thalamus to get to the cortex (refereed to as the gateway to the cerebrum).
• Almost every area of the thalamus activates its own specific region of cortex. This is vital for cortical activity.
• Might also be important for memory retrieval since damage to some thalamic areas results in retrograde amnesia.

Question 4

Attribute functions to the following areas of the brainstem: midbrain, pons, and medulla oblongata

Answer 4

Brainstem
- Links the spinal cord with the higher centres of the brain.

Midbrain

• Furthest from the spinal cord.
• Concerned with pupillary responses of the eye and eyeball orientation.

Pons

• Underneath the midbrain.
• Important for several unconscious activities.
• Important in control of urination.
• The pneumotaxic centre of the pons controls the rate and depth of breathing by communicating with the medulla oblongata.

Medulla oblongata

• Underneath the pons.
• Called the respiratory centre as neurones within it cause the respiratory muscles to contract and inspiration to occur.
• The pons and medulla oblongata play a role in controlling cardiac output and therefore blood pressure.

Question 5

Describe the pathways by which conducting nerve signals are carried by the spinal cord

Answer 5

• Carries both ascending and descending signals.
• Ascending signals are sensory in nature.
• Descending signals are motor in nature.
• Also mediates reflexes which are often protective in nature and also mediate functions including defaecation and urination.