ch 13

Question 1

ventricles of brain

Answer 1

lateral ventricles connected to third ventricle by interventricular foramen
third ventricle connected to fourth ventricle by cerebral aqueduct

Question 2

cranial meninges

Answer 2

1. dura mater (tough mother): most external layer, strongest meninx; 2 layers: outer layer periosteal layer, inner layer meningeal layer. these two layers always fused together except in areas where they are separated by dural sinuses
2. arachnoid mater: epithelial layer of arachnoid membrane and arachnoid trabeculae. separated from dura mater by subdural space. beneathe arachnoid membrain is subarachnoid space
3. pia mater (delicate mother): composed of delicate connective tissue that adheres directly to surface of brain, anchored by processes of astrocytes

Question 3

dural sinuses and dural folds

Answer 3

superior sagittal sinus: top sagittal
inferior sagittal sinus: inferior to superior sagittal sinus
transverse sinus: runs along transverse fissure
straight sinus: at end of superior sagittal sinus
dural folds:
1. falx cerebelli: separates both hemispheres of cerebellum
2. falx cerebri: separates both hemispheres of cerebrum
3. tentorium cerebelli : separates cerebrum from cerebellum

Question 4

cerebral spinal fluid (csf)

Answer 4

Function: mechanical protection: cushioning delicate neural structures; transports nutrients, chemical messengers and waste products.
Formation of CSF: choroid plexuses: consist of ependymal cells (joined together by tight junctions) + permeable, thin walled capillaries. ependymal cells secrete CSF into ventricles and remove watse products from csf
Circulation of CSF: circulates from choroid plexus through ventricles and fills central canal of spinal cord. through 2 lateral apertures and 1 median aperature in fourth ventricle, csf reaches subarachoid space, through arachnoid granulations, csf reaches the venous circulation at dural sinuses

Question 5

blood supply to brain

Answer 5

blood flow into brain: internal carotid arteries and vertebral arteries
blood flow out of brain: dural (venous) sinuses drains into jugular veins

Question 6

blood-brain barrier vs blood-csf barrier

Answer 6

BBB: isolates CNS neural tissue from general circulation; formed by network of tight junctions between endothelial cells; lipid-soluble compounds, steroids, and prostaglandins. Astrocyte controlled.
BCB: formed by special ependymal cells, surrounds capillaries of choroid plexus; limits movement of compounds transferred; allows chemical composition of blood and csf to differ

Question 7

cerebrum

Answer 7

left and right hemispheres.
gyri: precentral gyrus and postcentral gyrus
sulci: central sulcus; lateral cerebral sulcus; parieto-occipital sulcus
fissures: transverse fissure; longitudinal fissure
4 lobes: frontal, parietal, temporal, occipital and (insula)
3 basic regions: cerebral cortex, whit matter, basal nuclei

Question 8

motor areas

Answer 8

primary motor cortex
premotor cortex
frontal eye field
broca’s area

Question 9

primary motor cortex

Answer 9

located in precentral gyrus of frontal lobe
pyramidal cells: multipolar
control precise of skilled voluntary movement of skeletal muscle
form corticospinal tracts formed by long axons of pyramidal cells projecting to spinal cord
motor innervation of body is contralateral

Question 10

premotor cortex

Answer 10

memory bank for skilled motor activities (muscle memory)

responsible for coordination of learned movements

Question 11

frontal eye field

Answer 11

controls voluntary eye movement

Question 12

broca’s area

Answer 12

special motor speech area that directs muscles involved in speech production

Question 13

primary sensory cortex and somatic sensory association area

Answer 13

primary sensory cortex: receive information from general receptors
somatic sensory association area: monitors activity in primary sensory cortex; receives input from it. produces understanding of object being felt