Neuroscience 7 - The central nervous system Flashcards Preview

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Flashcards in Neuroscience 7 - The central nervous system Deck (33)
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1
Q

What is the spinal cord?

A

It is a column of segmental neural tissue. Each segment has a pair of spinal nerves attached to it.

2
Q

What does the grey matter and white matter consist of in the spinal cord?

A
  1. Grey matter = cell bodies.

2. White matter = axons.

3
Q

Where are the cell bodies of the sensory axons?

A

In the dorsal root ganglion.

4
Q

What is the dorsal horn of the grey matter?

A

The two horns of the grey matter facing back and they are sensory.

5
Q

What is the ventral horn of the grey matter?

A

The two horns of the grey matter facing the front and they consist of motor neurones.

6
Q

What does the spinal cord lie in? And what is the intervertebral foramina?

A

It lies in the vertebral canal in the vertebral column. The sides of the column also have a series of holes called intervertebral foramina - this is where spinal nerves come out of.

7
Q

What are the different spinal and vertebral levels? and how many nerves and vertebra are there in each?

A
  1. Cervical - 7 vertebra and 8 nerves.
  2. Thoracic - 12 vertebra and 12 nerves.
  3. Lumbar - 5 vertebra and 5 neurones.
    There is an unequal number of cervical nerves to vertebra as there is one nerve above C1.
8
Q

Is the spinal cord and vertebral column the same length? And why?

A

No, the spinal cord is much shorter. This is because the spinal cord finishes growing earlier on in development, whereas the vertebral column carries on growing for longer.

9
Q

What is the lumbar cistern?

A

The area where there is no spinal cord in the vertebral column. It contains cerebrospinal fluid which can be extracted using a needle in order to diagnose diseases of the central nervous system.

10
Q

What is the Cauda Equina?

A

The group of nerves located at the bottom of the vertebral column where there is no spinal cord.

11
Q

What are the functions of the spinal cord? (4)

A
  1. Connect PNS and ANS to the brain.
  2. Carries sensory signals to the brain.
  3. Carries motor signals to the muscles.
  4. Coordinates reflexes.
12
Q

How does the thickness of the spinal cord change?

A

The cervical and lumbar parts are thicker as innervations from the upper and lower limbs enter from there.

13
Q

What is the brain stem?

A
  1. It is made of the medulla, pons and the midbrain.
  2. It contains nuclei, which control vital functions such as the respiratory and cardiac centre.
  3. Descending and ascending neurones pass through from the brain to the spinal cord or vice versa.
  4. 10 of the 12 cranial nerves are attached to the brain stem.
14
Q

What is the diencephalon?

A
  1. The thalamus - higher up and is the relay station for information between the cerebral cortex and other parts of the CNS in both directions. Receives a lot of sensory information.
  2. Hypothalamus - inferior to the thalamus, important in coordinating homeostasis. Connected to the pituitary gland and important for hormone release.
15
Q

What is the Cerebral hemisphere?

A

Made of the cerebral cortex and basal ganglion. Is made of lots of nuclei.

16
Q

What is the basal ganglion?

A

Made of corpus striatum and lentiform nucleus. Control voluntary movement. Inhibits unwanted movement.

17
Q

What is the cerebral cortex?

A
  1. It Is divided into 4 lobes: frontal, temporal, parietal and occipital.
  2. Is made of gyri and sulci (invaginations).
  3. Deeper grooves are called fissures - longitudinal, cerebral and lateral - divide cortex into lobes.
18
Q

What are the 2 types of cortex in the hemisphere?

A
  1. Primary cortical areas - usually quite small and discrete and is where information is brought to.
  2. Associated cortex - larger, is where the information is elaborated and made sense of.
19
Q

What is a somatotopic arrangement?

A

Arranged like a body map - bottom controls head, middle controls arms and top controls legs.

20
Q

What does contralateral side mean?

A

It is the opposite side of the body to the side of the brain affected.

21
Q

What is the primary somatosensory cortex?

A

General sensory information from the body.

22
Q

What is the primary motor cortex?

A

Associated with movement. Axons from here travel down the descending pathway to stimulate motor neurones in spinal cord = stimulate muscle cells via PNS.

23
Q

What is the primary auditory cortex?

A

First to receive information from the ears.

24
Q

What is the primary visual cortex?

A

First to receive information from the retina.

25
Q

What is Wernicke’s area?

A

Important for understanding language.

26
Q

What is Broca’s area?

A

Important for speech.

27
Q

What is the limbic system?

A
  1. Contains the hippocampus and amygdala.

2. It is associated with memory, emotion and motivation.

28
Q

What is the cerebellum?

A
  1. It is attached posteriorly to the brain stem.
  2. Has a grey cortex with folds and deeper white matter with nuclei.
  3. Has 2 hemispheres and is divided into lobes.
  4. Refines movement: Ventricular system for balance, spinal cord for muscle tone, motor cortex for complex learned movements).
29
Q

How are different parts of the brain connected to each other?

A
  1. Through myelinated fibres.
  2. Commissural fibers = connect the two hemispheres.
  3. Associated fibers = connecting different parts of the same hemisphere.
  4. Projection fibers = connect different levels of the brain.
30
Q

What is the structure of the cranium?

A
  1. Made of 6 different bones.
  2. Has holes for veins and arteries (jugular foramen and carotid canal).
  3. Foramen megnum = where the medulla connects to the spinal cord.
31
Q

What are the layers of meninges?

A
  1. This is in the space between the brain and the bone.
  2. The dura is a tough fibrous layer.
  3. Arachnoid is web-like and has CSF and blood vessels.
  4. Venous sinuses also located - where venous blood collects to.
32
Q

Describe the structure of the ventricular system?

A
  1. 2 lateral C shaped ventricles, each in one hemisphere.
  2. The 2 lateral ventricles join to form the 3rd ventricle (lies in the middle of the diencephalon).
  3. The 3rd ventricle is connected via a duct to the 4th ventricle.
  4. The 4th ventricle then forms a fine channel called the central channel which goes down to the spinal cord.
33
Q

Where is CSF produced?

A

Produced by a special type of ependymal cell called choroid plexus, in the ventricle. CSF exits through the 4th ventricle and spreads outside the brain. CSF circulates in sub-arachnoid space between meninges and in reabsorbed by arachnoid villi.