6/10/2014 1 Brain stem- continuation of the spinal cord; consists of the medulla oblongata, pons and midbrain. Cerebellum- second largest part of the brain. Diencephalon- gives rise to thalamus, hypothalamus and epithalamus. Cerebrum- largest part of the brain.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
6/10/2014
1
Brain stem- continuation of the spinal cord; consists of the medulla oblongata, pons and midbrain.
Cerebellum- second largest part of the brain. Diencephalon- gives rise to thalamus,
hypothalamus and epithalamus. Cerebrum- largest part of the brain.
6/10/2014
2
The cranium The cranial meninges: dura mater, arachnoid
mater and pia mater.
Three extensions of the dura mater separate parts of the brain:
a. Falx cerebri separate the two cerebral hemispheres.
b. Falx cerebelli separate the two cerebellar hemispheres.
c. Tentorium cerebelli separate the cerebrum from the cerebellum.
6/10/2014
3
Brain receives approximately 20% of the total blood supply.
Internal carotid and vertebral arteries carry blood to the brain.
Internal jugular veins return blood from the brain.
Blood-brain barrier (BBB) protects brain from harmful substances.
Clear fluid. Circulates through cavities in the brain
(ventricles) and the spinal cord (central canal) and also in the subarachnoid space.
Absorbs shock and protects the brain and the spinal cord.
Helps transport nutrients and wastes from the blood and the nervous tissue.
6/10/2014
4
CSF-filled cavities within the brain. Lateral ventricles: cerebral hemispheres. Third ventricle: diencephalon. Cerebral aqueduct: midbrain. Fourth ventricle: brain stem and the cerebellum.
Choroid plexuses- networks of capillaries in the walls of the ventricles.
Ventricles are lined by ependymal cells. Plasma is drawn from the choroid plexuses through
ependymal cells into the ventricles to produce CSF.
6/10/2014
5
CSF from the lateral ventricles → interventricular foramina → third ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space or central canal.
CSF is reabsorbed into the blood by arachnoid villi.
Pyramids- Bulges on the
anterior aspect of the medulla. Formed by the large corticospinal tracts that pass from the cerebrum to the spinal cord.
A common site for decussation of ascending and descending tracts.
Vital centers: Cardiovascular center- Respiratory center- Also includes centers for vomiting,
swallowing, sneezing, coughing and hiccupping.
Houses five pairs of cranial nerves, VIII-XII. Portion of the ventricle found here is the
fourth ventricle.
6/10/2014
6
Extends from the pons to the diencephalon. Part of the ventricle found here- cerebral aqueduct. Cerebral peduncles: axons of the corticospinal,
corticopontine and corticobulbar tracts. Tectum- situated posteriorly and contains four
rounded elevations: two superior ones called superior colliculi and two inferior ones called inferior colliculi.
Substantia nigra: large area with dark pigments. Help control subconscious muscle activities. Loss of neurons here is associated with Parkinson disease.
Red nucleus: Help control voluntary
movements of the limbs. Contains cranial nerves III-IV.
6/10/2014
7
Extends from the upper part of the spinal cord, throughout the brain stem, and into the lower part of the diencephalon.
Part of the reticular formation called the
reticular activating system (RAS) consists of sensory axons that project to the cerebral cortex.
The RAS helps maintain consciousness.
Second largest part of the brain. The central constricted area is the vermis. The anterior and posterior lobes control
subconscious aspects of skeletal movement. The flocculonodular lobe on the inferior side
contributes to the equilibrium and balance.
6/10/2014
8
Cerebellar cortex- gray matter in the form of parallel folds called folia.
Arbor vitae- tracts of white matter. Cerebellar peduncles- three pairs: superior,
middle and inferior. Attach cerebellum to the brain stem.
Functions- coordinate movements, regulate posture and balance.
6/10/2014
9
Intermediate mass Several nuclei: Major relay station for
most sensory impulses.
Inferior to the thalamus. Consists of mammillary body, median eminence,
infundibulum, and a number of nuclei.
Control of the ANS. Production of hormones Regulation of emotional and behavioral
patterns, eating and drinking, body temperature, and circadian rhythms.
6/10/2014
10
Small region superior to the thalamus. Consists of pineal gland which secretes a
hormone called melatonin. Melatonin induces sleep.