Lab 8

Question 1

What are the 3 main protective structures of the CNS?

Answer 1

1. Skull and vertebral column
2. Meninges
3. Cerebrospinal fluid

Question 2

Sutures

Answer 2

Immovable joints that join together all the bones in the adult skull (besides the mandible and 3 ear bones)

Question 3

Foramina

Answer 3

Several small holes in the skull that cranial nerves exit out of.

Question 4

Foramen magnum

Answer 4

One large hole at the base of the skull which the spinal cord passes through

Question 5

Vertebral foramen

Answer 5

A large hole in each vertebra through which that spinal cord passes through

Question 6

Meninges

Answer 6

3 layers of connective tissue that cover the surface of the brain and spinal cord

3 layers:
- dura mater
- arachnoid mater
- pia matter

Question 7

Dura mater

Answer 7

The outermost layer of the meninges, it’s made up of fibrous connective tissue.

2 subdivisions:
1. Periosteal dura mater - outmost layer of dura mater which is attached to inner surface of bone of the skull.

2. Meningeal dura mater - inner layer of dura matter which forms the actual external covering over the brain

Question 8

Arachnoid mater

Answer 8

The middle layer of the meninges, it is separated from dura mater by a small film of serous fluid.

Beneath it is the subarachnoid space which contains cerebrospinal fluid and blood vessels

Question 9

Pia mater

Answer 9

The innermost layer of meninges. Contains highly vascular areolar connective tissue.

Question 10

Cerebrospinal fluid

Answer 10

A watery fluid that fills the 4 ventricles of the brain and central canal. Acts as a cushion for the whole CNS since it protects the soft tissue from various blows.

Question 11

Choroid plexuses

Answer 11

Found at the top of each ventricle, it produces cerebrospinal fluid within its capillaries

Question 12

Arachnoid villi

Answer 12

Knobby projections of the arachnoid material which absorb the cerebrospinal fluid

Question 13

Corpus callosum

Answer 13

A large bundle of nerve fibres connecting the cerebral hemispheres and conducting nerve impulses between them.

Question 14

Cerebral aqueduct

Answer 14

Travels along the midbrain region and connects the 3rd and 4th ventricles

Question 15

Cerebrum

Answer 15

The largest portion of the brain.

The entire upper portion with folds (gyri) and grooves (sulci)

Note: deeper grooves within the cerebrum are fissures (ex. The groove between the 2 hemispheres)

Question 16

Longitudinal fissure

Answer 16

The fissure which separates the cerebrum into right and left cerebral hemispheres

Question 17

Cerebellum

Answer 17

Located underneath the cerebrum and behind spinal cord.

It is responsible for involuntary coordination of skeletal muscle and the control of balance.

Question 18

Midbrain

Answer 18

Lies under the cerebrum. It transmits information necessary for vision and hearing

Question 19

Corpora quadrigemina

Answer 19

Controls the position of the head and eyes in response to various auditory/visual stimuli

Question 20

Pons

Answer 20

Lies under the midbrain. Contains fibres that connect parts of the cerebellum with the cerebrum

Involved in unconscious processes such as sleeping and breathing

Question 21

Medulla oblongata

Answer 21

Transmits signals between the spinal cord and the rest of the brain. It also controls things like heartbeat and respiration

Question 22

Central sulcus

Answer 22

Separates the frontal lobe from the parietal lobe

Question 23

Lateral sulcus

Answer 23

Separates the frontal lobe from the temporal lobe

Question 24

Precentral gyrus

Answer 24

The gyrus in front of the central sulcus and part of the frontal lobe.

It contains the primary motor area which controls voluntary movement of skeletal muscles

Question 25

Postcentral gyrus

Answer 25

The gyrus behind of the central sulcus and part of the parietal lobe. Contains the primary sensory area which receives info from sensory receptors for pressure, pain, and temperature.

Question 26

Thalamus

Answer 26

An important relay station for sensory impulses passing upward to the cerebral cortex. (All sensory info must be processed in thalamus except olfactory)

Question 27

Hypothalamus

Answer 27

Directly under the thalamus. Helps regulate body temp, water balance, appetite. In general it maintains homeostasis!

Question 28

I. Olfactory nerve

Answer 28

Function: Sensory - carries impulses associated with sense of smell Superficial origin: From nasal mucosa to olfactory bulb

Question 29

II. Optic nerve

Answer 29

Function: **Sensory** - carries impulse as associated with vision Superficial origin: From retina to optic chiasma

Question 30

III. Oculimotor nerve

Answer 30

Function: **Motor** - (1) controls 4/6 eye muscles which move the eye ( (2) controls ciliary muscle which changes lens based on distance (3) controls smooth muscle of iris to constrict the pupil Superficial origin: Midbrain

Question 31

IV. Trochlear nerve

Answer 31

Function: **Motor** - controls 1/6 eye muscles which move the eye (superior oblique) Superficial origin: Midbrain

Question 32

V. Trigeminal nerve

Answer 32

Function: **Sensory**- (Ophthalmic) Pain, touch, and temp from nasal mucous membrane, facial skin, cornea ( Maxillary) Pain, touch, and temp from facial skin, mouth, upper teeth (Mandibular) pain, touch, and temp from chin, lower teeth, tongue **Motor** - muscles of chewing Superficial origin: Pons

Question 33

VI. Abducens nerve

Answer 33

Function: **Motor** - controls 1/6 eye muscles which move the eye (lateral rectus) Superficial origin: Pons

Question 34

VII. Facial nerve

Answer 34

Function: **Sensory** - taste from tongue **Motor** - muscles of face, ears, scalp responsible for facial expression. Secretion of saliva and tears Superficial origin: Pons

Question 35

VIII. Vestibulocochlear nerve

Answer 35

Function: **Sensory**- (Cochlear) carries impulses associated hearing (Vestibular) registers movement of body through position of head. Communicates with cerebellum to maintain homeostasis and coordination of muscle function Superficial origin: Groove between pons and medula oblongata

Question 36

IX. Glossopharyngeal nerve

Answer 36

Function: **Sensory** - touch, temp, and pain from pharynx. Taste from tongue **Motor** - muscles of pharynx and base of tongue. Also stimulates secretion of salivary gland Superficial origin: Medulla oblongata

Question 37

X. Vagus nerve

Answer 37

Function: **Sensory** - receptors from the larynx, trachea, lungs, esophagus, stomach, intestine, gall bladder, epiglottis **Motor** - muscles of larynx for swallowing. Smooth muscle of digestive tract to keep things moving. Cardiac muscle to slow heart rate Superficial origin: Medulla oblongata

Question 38

XI. Spinal accessory nerve

Answer 38

Function: **Motor** - muscles of pharynx, larynx, palate, spinal cord muscles. Mainly swallowing and movement of head and shoulders Superficial origin: Medulla oblongata and spinal cord

Question 39

XII. Hypoglossal nerve

Answer 39

Function: Motor - muscles of tongue. Movement of tongue during speech and swallowing Superficial origin: Medulla oblongata

Question 40

5 components of a basic reflex arc

Answer 40

1. receptors 2. sensory neurons 3. integrating neurons 4. motor neurons 5. effector organ (usually a muscle)