BRAIN Flashcards
Brain Protection:
Cranial Meninges
(a) Dura mater: Outer most layer
(b) Arachnoid mater: Middle layer
(c) Pia mater: Inner layer
Only____of the body’s weight, but requires ____ of the body’s oxygen supply.
2%
20%
Circulatory anastomosis that supplies blood to brain and surrounding structures; stems from the two internal carotid arteries.
“Circle of Willis”
Blood brain barrier allows passage of
lipid soluble materials such as O2, CO2, alcohol, anesthesia
Cerebrospinal Fluid
a. Circulates through the subarachnoid space around the brain and spinal cord, central canal,
and through cavities in the brain called ventricles.
Brain Stem contains the
medulla oblongata, pons, and midbrain
Diencephalon contains the
thalamus, hypothalamus, and pineal gland
Cerebellum
“little brain;”
Functions for balance and equilibrium and coordination
Cerebrum
Largest, most superior part
Three major regions : Brain Stem
Medulla Oblongata
Pons
Midbrain
Medulla Oblongata Characteristics
Regulates the rate and force of the heart and the diameter of the vessels
Medullary rhythmicity area regulates breathing
Nuclei associated with touch, pressure, vibration and proprioception lie in the posterior part of the medulla.
Associated with cranial nerves VIII-XII
Pons Characteristics
“Bridge” medulla to the midbrain and above
Ascending (sensory) and descending (motor) tracts
Contains nuclei
a) Motor relay from cerebrum to cerebellum
b) Helps control breathing
c) associated with cranial nerves V-VIII
Midbrain Characteristics
Connects the pons to the diencephalon
Associated with cranial nerves CN III and IV
Midbrain Characteristics:
Cerebral peduncles
Large tracts that contain axons of motor neurons from cerebrum to rest of brainstem and spinal cord
Midbrain Characteristics:
Red nuclei
Coordinate muscular movement
Midbrain Characteristics:
Superior colliculi
involved in scanning eye movement and responses to visual
stimuli
Midbrain Characteristics:
Inferior colliculi
response to auditory input and startle reflex
Diencephalon:
Thalamus
1) Major sensory relay center
2) Contributes to motor functions
3) Plays role in consciousness
Diencephalon:
Hypothalamus
1) Lies inferior to thalamus and superior to the pituitary gland; important for homeostasis
2) Control of pituitary and hormone production
3) Control and integration of the ANS
4) Regulation of emotional and behavior patterns
5) Regulation of eating and drinking
6) Control of body temperature
7) Regulation of circadian rhythms, sleep and awakening patterns
Diencephalon:
Pineal Gland (part of the endocrine system)
Secretes melatonin which promotes sleepiness and contributes to setting the body’s
biological clock
Cerebellum
Tree-like appearance (seen in sagittal section) of white matter and gray nuclei
Cerebellum Functions
(a) Receives wide range of sensory input from muscles, joints, tendons, eyes, equilibrium
receptors in inner ears and visual receptors
(b) Compares actual movements with intended ones
(c) Helps to smooth and coordinate skeletal muscle contractions
(d) Helps execute skilled motor activities
(e) Regulates posture and balance essential for skilled motor activities
Cerebrum Structure:
Longitudinal Fissure
Divides the cerebrum into right and left cerebral hemispheres