sistemul nervos

Question 1

When did people begin to think that the brain was important?

Answer 1

In the 1800s. Before that people used to chuck away the brain. They thought the heart was more important and that the brain was involved in thermoregulation.

Question 2

What did Luigi Galvani do?

Answer 2

He put electrical current through a frog’s leg and made the legs twitch.
Thus discovering the electrical basis of nerves.

Question 3

What did Helmholtz do?

Answer 3

He measured the speed of nerve conduction.

Question 4

What did Ramon y Cajal do?

Answer 4

Described how nerve cells communicate

Question 5

History of MRI

Answer 5

1947 - first discovered
1977 - first clinical images
1982 - first brain MRI
1990s - commonly used in the UK

Question 6

What are the sub-divisions of the nervous system>

Answer 6

Central nervous system and peripheral nervous system

Question 7

What are the sub-divisions of the central nervous system

Answer 7

Brain and spinal cord

Question 8

what are the sub-divisions of peripheral nervous system

Answer 8

somatic and autonomic nervous system

Question 9

what are the sub-divisions of the autonomic nervous system

Answer 9

sympathetic and parasympathetic

Question 10

Roles of the brain and spinal cord

Answer 10

The brain receives and processes sensory information and then initiates appropriate responses
The spinal cord is the principal route for this information to and from the brain

Question 11

How are the brain and spinal cord protected?

Answer 11

The brain and spinal cord are highly protected:
- encased in bone (skull and vertebrae)
- surrounded by meninges (3 membranes that line the skull and vertebral canal)
- cerebrospinal fluid (CSF)

Brain is guarded from chemical invasion by the blood brain barrier (BBB)

Question 12

How is the spinal cord protected?

Answer 12

The spinal cord is encased by the vertebral column, which provides protection.
It is the main pathway for information between the brain and the peripheral nervous system.

Question 13

What is grey and white matter?

Answer 13

In the brain: grey matter is outer layer, white matter is inner layer
In the spinal cord: grey matter is inner layer, white matter is outer layer

Grey matter consists of densely packed neuronal cell bodies and other cells.
White matter contains mainly myelinated axons that allow communications between cells.

Question 14

What are meninges?

Answer 14

In the CNS, there are 3 protective layers that surround the brain and spinal cord.

1. Dura mater: thick, flexible, unstretchable
2. Arachnoid membrane: middle, below dura. soft
3. Pia mater: lower and delicate closely attached to the brain and spinal cord

In the PNS there are only 2 layers: dura and pia mater

Question 15

What is the cerebral spinal fluid

Answer 15

A clear fluid which helps protect the brain and spinal cord from damage.
Removes waste products.
Acts as a cushion
Provides hormones and nutrition

Question 16

Where is cerebral spinal fluid found in the CNS?

Answer 16

Subarachnoid space: the gap between the arachnoid membrane and the pia mater

Ventricles: hollow, interconnected chambers within the brain

Central canal: of the spinal cord

CSF is secreted within the ventricles

Question 17

What is the BBB?

Answer 17

The BBB is a barrier of capillaries without gaps between the blood and the brain

BBB helps regulate the composition of the fluid which surrounds neurones, important for synaptic transmission and brain function

It allows certain substances in and only certain substances out

Question 18

Is BBB consistent throughout the brain>

Answer 18

No. A weak spot is at area postrema in the medulla.
Area postrema controls vomiting.
Neurones in the area postrema can detect toxins, and vomiting can be initiated.

Question 19

What does the PNS consist of?

Answer 19

Nerves (cable-like bundles of axons) and ganglia (clusters of cell bodies) that are outside of the CNS.

These connect the CNS to the limbs and organs

There are 12 pairs of cranial nerves in the brain that establish connections in the head and upper body

There are 31 pairs of spinal nerves that do the same for the rest of the body.

Question 20

What do cranial nerves do?

Answer 20

Mostly involved with motor and sensory functions of the head and neck.
Vagus nerve: regulates functions of internal organs located in thoracic and abdominal cavities e.g. heart and intestines

Question 21

What do spinal nerves do?

Answer 21

The Bell-Magendie Law states that the spinal cord contains:
Descending motor information (efferent signals carried away from the CNS via the ventral root to muscle or glands)

Ascending somatosensory information (afferent signals carried toward the CNS via the dorsal root)

Question 22

What does the PNS do?

Answer 22

The CNS receives information from the PNS, which senses signals from outside of the body (somatic) and from inside the body (autonomic)

Question 23

What is the sympathetic and parasympathetic?

Answer 23

Symp: Fight or flight
Parasymp: rest and digest