Lab 8 Flashcards
What are the 3 main protective structures of the CNS?
- Skull and vertebral column
- Meninges
- Cerebrospinal fluid
Sutures
Immovable joints that join together all the bones in the adult skull (besides the mandible and 3 ear bones)
Foramina
Several small holes in the skull that cranial nerves exit out of.
Foramen magnum
One large hole at the base of the skull which the spinal cord passes through
Vertebral foramen
A large hole in each vertebra through which that spinal cord passes through
Meninges
3 layers of connective tissue that cover the surface of the brain and spinal cord
3 layers:
- dura mater
- arachnoid mater
- pia matter
Dura mater
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.
- Meningeal dura mater - inner layer of dura matter which forms the actual external covering over the brain
Arachnoid mater
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
Pia mater
The innermost layer of meninges. Contains highly vascular areolar connective tissue.
Cerebrospinal fluid
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.
Choroid plexuses
Found at the top of each ventricle, it produces cerebrospinal fluid within its capillaries
Arachnoid villi
Knobby projections of the arachnoid material which absorb the cerebrospinal fluid
Corpus callosum
A large bundle of nerve fibres connecting the cerebral hemispheres and conducting nerve impulses between them.
Cerebral aqueduct
Travels along the midbrain region and connects the 3rd and 4th ventricles
Cerebrum
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)
Longitudinal fissure
The fissure which separates the cerebrum into right and left cerebral hemispheres
Cerebellum
Located underneath the cerebrum and behind spinal cord.
It is responsible for involuntary coordination of skeletal muscle and the control of balance.
Midbrain
Lies under the cerebrum. It transmits information necessary for vision and hearing
Corpora quadrigemina
Controls the position of the head and eyes in response to various auditory/visual stimuli
Pons
Lies under the midbrain. Contains fibres that connect parts of the cerebellum with the cerebrum
Involved in unconscious processes such as sleeping and breathing
Medulla oblongata
Transmits signals between the spinal cord and the rest of the brain. It also controls things like heartbeat and respiration
Central sulcus
Separates the frontal lobe from the parietal lobe
Lateral sulcus
Separates the frontal lobe from the temporal lobe
Precentral gyrus
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
Postcentral gyrus
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.
Thalamus
An important relay station for sensory impulses passing upward to the cerebral cortex.
(All sensory info must be processed in thalamus except olfactory)
Hypothalamus
Directly under the thalamus.
Helps regulate body temp, water balance, appetite. In general it maintains homeostasis!
I. Olfactory nerve
Function:
Sensory - carries impulses associated with sense of smell
Superficial origin:
From nasal mucosa to olfactory bulb
II. Optic nerve
Function:
Sensory - carries impulse as associated with vision
Superficial origin:
From retina to optic chiasma
III. Oculimotor nerve
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
IV. Trochlear nerve
Function:
Motor - controls 1/6 eye muscles which move the eye (superior oblique)
Superficial origin:
Midbrain
V. Trigeminal nerve
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
VI. Abducens nerve
Function:
Motor - controls 1/6 eye muscles which move the eye (lateral rectus)
Superficial origin:
Pons
VII. Facial nerve
Function:
Sensory - taste from tongue
Motor - muscles of face, ears, scalp responsible for facial expression. Secretion of saliva and tears
Superficial origin:
Pons
VIII. Vestibulocochlear nerve
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
IX. Glossopharyngeal nerve
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
X. Vagus nerve
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
XI. Spinal accessory nerve
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
XII. Hypoglossal nerve
Function:
Motor - muscles of tongue. Movement of tongue during speech and swallowing
Superficial origin:
Medulla oblongata
5 components of a basic reflex arc
- receptors
- sensory neurons
- integrating neurons
- motor neurons
- effector organ (usually a muscle)
