Chapter 14: The brain and cranial nerves

Question 1

describe the appearance of the brain

Answer 1

2 fistfuls, , inkish gray tissue, wrinkled like a walnut, with texture of cold oatmeal.

Question 2

Name four major regions of the brain

Answer 2

brainstem, cerebellum,
diencephalon, and cerebrum

Question 3

Describe the protective covering of the brain.

Answer 3

The brain is protected by the cranium and cranial meninges:-
**Dura matter has two layers unlike the spinal dura (periosteal-external and meningeal internal)
**Arachnoid mater
**Pia mater

Question 4

What is the BBB, describe and state its function.

Answer 4

surrounded by capillaries and is selectively permeable to some substances. For instance water soluble substances, some steroids. It prevents entry of proteins and some drugs.

Question 5

Describe CSF

Answer 5

a clear, colorless liquid composed primarily of water that protects the brain and spinal cord from chemical
and physical injuries.
** It fills the ventricles
-lateral ventricles 1 and 2 separated by septum pellucidum
-third ventricle
-fourth ventricle btwn brainstem and cerebellum.

Question 6

What are the 3 basic functions of the CHF

Answer 6

** shock absorber protecting the delicate tissues of the brain.
**provides an optimal chemical environment for accurate neuronal signalling.
** medium of exchange of nutrients and waste in the blood and nervous tissue.

Question 7

Where/how is CHF produced?
See image in page 463 of the CHF circulation.

Answer 7

-majority of CSF production is from the choroid plexuses of each lateral ventricle.
-CS fluid is filtered from the blood plasma by capillaries.(tight junctions prevent leaking).
-CSF is gradually reabsorbed into the blood through arachnoid
villi.
**rates of formation and reabsorption are the same, the pressure of CSF normally is constant.

Question 8

Brain stem

Answer 8

consists of
**Pons
** mid brain
** Medullar oblongata

Question 9

medullar Oblongata

Answer 9

begins at the foramen magnum
and extends to the inferior border of the pons.
- contains many nuclei that regulate vital visceral activities ie control HR, BP, swallowing, Breathing, vomiting.
- Contains cranial nerves vestibulocochlear (VIII) nerves, glossopha
ryngeal
(IX) nerves, vagus (X) nerves, accessory (XI) nerves
(cranial portion), and hypoglossal (XII) nerves

Question 10

Pons

Answer 10

** serves as a relay station for sensory information between the cerebrum and the cerebellum.
** nuclei involved in regulating respiration.
**trigeminal (V) nerves, abducens (VI) nerves, facial (VII)nerves, and vestibulocochlear (VIII) nerves.

Question 11

mid brain

Answer 11

**Superior colliculi coordinate
movements of head, eyes, and trunk in response to visual stimuli.
**Inferior colliculi coordinate
movements of head, eyes, and trunk
in response to auditory stimuli.
**The substantia nigra and red nucleus contribute to control
of movement.
**oculomotor (III)
nerves and trochlear (IV) nerves.

Question 12

2. Diencephalon

Answer 12

thalamus, hypothalamus and peneal gland.

Question 13

functions of the thalamus

Answer 13

The major relay station for most sensory impulses that reach the cerebral cortex from the spinal cord and brain stem.

Question 14

Hypothalamus

Answer 14

**control activities of the ANS.contraction of smooth and cardiac muscle and the secretions of many glands.
**Control of the pituitary gland and production of hormones ie release of ADH and oxytocin stored in the pituitary gland.
**hypothalamus regulates feelings of rage, aggression, pain, and pleasure, and the behavioral patterns related to
sexual arousal.
**Regulation of eating and drinking.
**Control of body temperature
**Regulation of circadian rhythms and states of consciousness, sleep.

Question 15

3. Cerebellum

Answer 15

-located posterior to the medulla and pons and inferior
to the cerebrum.
-cerebellar cortex, consists of gray matter.
-helps to smooth and coordinate complex sequences of skeletal muscle contractions. It regulates posture
and balance and is essential for all skilled motor activities.

Question 16

4.cerebrum

Answer 16

-provides us with the ability to read,
write, and speak; to make calculations and compose music; to remember the past and plan for the future; and to create.
-folds are called gyri
-The deep grooves between folds are fissures; the shallow grooves are sulci.
-cerebral hemisphere has four lobes that are named after the bones that cover them: frontal lobe, parietal lobe,
temporal lobe, and occipital lobe.