Gross Anatomy of The Brain Pt. II

Question 1

What is the corpus callosum?

Answer 1

White matter that links the two cerebral hemispheres allowing communication

Question 2

What are corona radiata?

Answer 2

Myelinated axons (white matter) that pass through the corpus callosum

Question 3

Describe the internal capsule

Answer 3

Has an anterior limb and posterior limb which join to form a V shape around the lentiform nucleus

Question 4

What makes up the lentiform nucleus?

Answer 4

The plutamen
The globule pallidus

Question 5

What are basal nuclei?

Answer 5

Grey matter areas of cell bodies primarily involved in motor control but can have other roles
They project neurones into the thalamus which is involved in relaying this information to the cerebral cortex

Question 6

Name the basal nuclei

Answer 6

(Basal ganglia)
Corpus striatum (caudate nucleus and lentiform nucleus)
Substantial Nigra
Subthalamic nucleus

Question 7

Where is the hypothalamus found?

Answer 7

Inferior and anterior to the thalamus

Question 8

What does the hypothalamus do?

Answer 8

Involved in maintaining homeostasis by monitoring internal environment and controlling autonomic systems
Controls release of hormones from pituitary which is connected via the pituitary stalk

Question 9

What does the pituitary gland do?

Answer 9

Regulates hormone release through releasing or inhibiting hormones

Question 10

Where is the pituitary gland found?

Answer 10

Continuous with the hypothalamus inferiorly in the middle cranial fossa and sella turcica

Question 11

Give examples of hormones released from the pituitary gland

Answer 11

Growth hormone
Thyroid stimulating hormone
Follicle stimulating hormone

Question 12

What causes acromegaly?

Answer 12

Over production of growth hormone by the pituitary gland
Most commonly pituitary tumour and due to slow growth of these can take years for symptoms to arise and a diagnosis to be made

Question 13

What are the symptoms of acromegaly?

Answer 13

Growth of hands and feet
Lips, nose and tongue become larger
Voice becomes deeper
Increase in size of jaw leading to gaps between teeth

Question 14

What can untreated acromegaly lead to?

Answer 14

High blood pressure
Diabetes
Sleep apnoea

Question 15

What are ventricles and what do they do?

Answer 15

Cavities within the brain filled with CSF to protect the brain
They produce and circulate CSF

Question 16

How is CSF produced?

Answer 16

By choroidal epithelial cells (modified endymal cells) of choroid plexus which are located in each ventricle

Question 17

What ventricles are found in the brain?

Answer 17

2 lateral ventricles, one in each hemisphere
Midline 3rd ventricle
Midline 4th ventricle

Question 18

What separates the lateral ventricles?

Answer 18

The septum pellucidum

Question 19

What connects the lateral ventricles to the 3rd ventricle?

Answer 19

The interventricular foramen

Question 20

What connects the 3rd and 4th ventricles?

Answer 20

The cerebral aqueduct

Question 21

What happens to CSF in the 4th ventricle?

Answer 21

Leaves via lateral apertures and median aperture into subarachnoid space

Question 22

What is the brainstem?

Answer 22

The connection between the cerebrum, cerebellum and spinal cord

Question 23

What is found in the brainstem?

Answer 23

Can be split into midbrain, pons and medulla
Contains many nuclei and neuronal tracts and is the region where cranial nerves exit the brain

Question 24

Where does the spinal cord begin and end?

Answer 24

Begins at foramen magnum of skull as continuation of medulla
Ends at L1/L2 vertebrae in adults

Question 25

Describe the inferior end of the spinal cord

Answer 25

Known as the conus medullaris and continues as the film terminale (pia mater)

Question 26

How long is the average spinal cord?

Answer 26

42 - 45 cm long

Question 27

Where are enlargements in the spinal cord found?

Answer 27

Cervical enlargement between C4-T1 - contributes to the brachial plexus
Lumbosacral enlargement between T11-S1 - contributes to the lumbosacral plexus

Question 28

Describe the internal structure of the spinal cord

Answer 28

Grey matter surrounded by white matter
Grey matter forms H shape comprising of ventral horns, lateral horns and dorsal horns
White matter forms the anterior column, lateral column and dorsal column
Central canal found in the middle of the grey matter

Question 29

How are spinal nerves formed?

Answer 29

Rootlets emerge from the horns of the spinal cord which converge to become roots which form the spinal nerves

Question 30

Which type of roots emerge from the ventral horns?

Answer 30

Efferent motor fibres which carry information from the CNS to the PNS

Question 31

Which type of roots emerge from dorsal horns?

Answer 31

Sensory afferent roots which carry information from the periphery to the CNS

Question 32

What happens when afferent and efferent fibres converge to form a spinal nerve?

Answer 32

They pass through the intervertebral foramina as a mixed structure then divide to form ventral and dorsal rami
These rami contain both sensory and motor fibres however will have a primary function - either sensory or motor

Question 33

Where do spinal nerves emerge?

Answer 33

All emerge between adjacent vertebrae except C1 which emerges between the occipital bone of the skull and C1 (atlas)

Question 34

How are cervical spinal nerves numbered

Answer 34

According to the vertebra below
C8 is an exception - there are 7 cervical vertebrae and 8 spinal nerves

Question 35

How many thoracic, lumbar, sacral and coccygeal nerves are there and how are they numbered?

Answer 35

12 Thoracic
5 Lumber
5 Sacral
1 Coccygeal
Numbered according to the vertebra above

Question 36

How is the spinal cord protected?

Answer 36

3 meningeal layers
Dura mater - outer
Arachnoid matter - middle
Pia mater - inner
Deep to the pia mater is subarachnoid space with CSF

Question 37

What are myotomes?

Answer 37

Anatomically and functionally related groups of skeletal muscles (links with embryology) that are supplied by a specific single spinal nerve

Question 38

What are dermatomes?

Answer 38

Localised areas of skin which are supplied by a specific single spinal nerve