How Nerves Work 1

Question 1

Discuss the subdivisions of the Nervous System

Answer 1

The brain and spinal cord make up the CNS whilst the peripheral nerves make up the PNS.
The autonomic nervous system controls subconscious things like BP etc.
The somatic nervous system controls things which we voluntarily think about doing.
The enteric nervous system system helps govern the GI tract.

Question 2

Describe the structure of the brain

Answer 2

The brain has four lobes: the frontal, parietal, temporal and occipital lobe. 
It has the cerebrum and the cerebellum which are both split into two hemispheres. The corpus callosum connects the two hemispheres of the brain. 
The diencephalon is split into the thalamus (relays sensory info) and the hypothalamus (interaction of hormone and nervous systems). 
The brainstem is split into the midbrain, the pons ( connects two halves of the cerebellum) and the medulla oblongata (has Neurons to monitor Bp and respiratory system). 
The gyrus (high) and sulcus (low) are grooves of the brain which allow more Neurons. Meninges allow Cerebral spinal fluid to protect the brain.

Question 3

How many pairs of spinal nerves are there and where are they found?

Answer 3

31 pairs of spinal (12 cranial)
8 Cervical (arms, shoulders and neck)
12 thoracic (chest and abdomen)
5 lumbar (hips and legs)
5 Sacral (genitalia and GI tract)
1 coccygeal

Question 4

Describe the spinal cord in terms of the root of a current.

Answer 4

A current would enter along the afferent (sensory) route into the dorsal horn and leave out the ventral horn and along the efferent (motor) neurones.
Interneurones are in the grey matter and white matter is axons (covered in myelin which is white).
Spinal tracts take information up to the brain.

Question 5

Describe the structure and function of a neurone

Answer 5

The soma is the cell body.
Dendrites receive information from other cells.
Initial segment (axon hillock) triggers action Potentials.
Axon sends action Potentials.
Presynaptic axon terminals release neurotransmitters.

Question 6

Name four types of Glia and their functions.

Answer 6

Astrocytes are used to maintain the external environment for the neurone and they surround blood vessels and help form the blood brain barrier.
Oligodendrocytes form myelin sheaths in the CNS.
Microglia act as phagocytic hoovers that clear up infection.
Ependymal cells help produce cerebral spinal fluid.