the brain Flashcards
1
Q
what are the functions of the brain?
A
- controls heart rate, respiration, blood pressure, and maintains homeostasis
- innervation of the head and neck
- high-level tasks: intelligence, conciousness, memory, emotion, behavior
2
Q
what are the four main parts of the brain?
A
- cerebrum
- diencephalon
- cerebellum
- brain stem (midbrain, pons, medulla oblongata)
3
Q
what is white and gray matter?
A
- gray matter is on the outermost part of the brain (cerebellar + cerebral cortex) and also the innermost regions (cerebral nuclei)
- gray matter is unmyelinated neurons and neuron cell bodies
- white matter is made of myelinated axons, lies deep to the cortex of the brain
4
Q
what is the diencephalon?
A
- surrounded by the cerebral hemispehere
- contains the 3rd ventricle
- lateral walls: thalamus
- floor: hypothalamus
- roof: epithalamus
5
Q
what is the thalamus?
A
- forms lateral walls of the 3rd ventricle
- filters somatosensory, visual, and auditory information (all except smell)
- ANY PART OF THE BRAIN (SENSORY OR NOT) THAT COMMUNICATES WITH CEREBRAL CORTEX MUST GO THROUGH THALAMUS
6
Q
what is the hypothalamus?
A
- main visceral control center of the body, regulates many activities
- controls autonomous nervous system
- regulates body temperature
- regulates hunger and thirst
- regulates sleep-wake cycle
- controls endocrine system
- controls emotional responses
- formation of memory
7
Q
what is the epithalamus?
A
- forms roof of the 3rd ventricle
- includes pineal gland
+ endocrine function, secretes melatonin for circadian rhythm
8
Q
what is the cerebrum?
A
- divides into 2 halves: left and right hemispehere
- each hemisphere is divided into 5 distinct lobes: frontal, parietal, occipital, temporal, insula (named for overlapping bones)
9
Q
what are gyri and sulci?
A
- gyri: ridges of brain tissue. ridges allow for more cerebral cortex to fit in the cranial vault (precentral and procentral)
- sulci: grooves between the gyri (central, parieto-occipital, and lateral
10
Q
what are the cerebral functions?
A
- intelligence, complex thinking
- 3 types of functional areas:
+ sensory: conscious awareness of sensation
+ association areas: intergrates information - motor areas: voluntary motor functions
11
Q
what is the primary somatosensory cortex?
A
- receives information from somatic senses (touch, pressure, vibration, pain, proprioception)
- enables consciousness awareness of the senses. located in post-central gyrus
12
Q
what is the primary auditory + primary visual cortexes
A
- PVC: posterior/medial occipital lobe. receives visual information from the retina
- PAC: primary auditory cortex. receives and processes auditory information from the inner ear
13
Q
what is broca’s area?
A
- motor-speech area; controls motor movements for speech
- if damaged, can’t understand speech, but not speak fluently
14
Q
what is wernicke’s area?
A
- multimodal association area
- recognition and understanding of speech
- if damaged, can speak, but not comprehend language
15
Q
what is the white matter of the cerebrum?
A
- corpus callosum: largest visible band of comissural fibers (connects 2 halves)
- association fibers: short fibers that connect regions in the same hemisphere
16
Q
what is the cerebral neural (deep gray matter)?
A
- deep, paired masses of gray matter. AKA basal nuclei (ganglia)
- involved in motor control
- include caudate nucleus, putamen, amygdala, and globus pallidus. generally, cerebral nuclei start, stop, and regulate the intensity of voluntary movement
17
Q
what is the function of the brainstem?
A
- made up of the midbrain, pons, and medulla oblongata
- connects cerebrum and spinal cord
- start of the cranial nerves for innervations of the face and head
- autonomic and reflex centers needed for survival
18
Q
what is the midbrain?
A
- located between the diencephalon and pons
- internal cavity is cerebral aqueduct (part of brain ventricles)
- tectal plate: site for reflexes
- superior colliculi for visual reflexes
- inferior colliculi response to sound
19
Q
what is the pons?
A
- located between midbrain and medulla
- separated from cerebellum by 4th ventricle
20
Q
what is the medulla oblongata?
A
- most caudal part of the brain stem, continuous with spinal cord
- pyramid carry voluntary motor output from cerebrum to spinal cord
- fibers “decussate” or cross-over, so left controls right, and right controls left
21
Q
what is the cerebellum?
A
- functions:
+ fine-tunes/tweaks body movements
+ coordinates body movement
+ maintain posture and equilibrium - 2 hemispheres connected by vermis
- folia are leaf-like folds that increase surface area
- outer cortex is gray matter, white matter is arbor vitae
- processing:
+ receives information from cerebrum on movements planned
+ compares planned movement with current body position
+ sends instructures back to cerebral cortex to readjust/refine motor commands
22
Q
what is the limbic system?
A
- involved with emotion and motivation, creatining, storing, and retreiving memories
- includes:
+ cingulate gyrus: emotional response
+ hippocampus: stores memory
+ amygdala: processes fear - all are linked together byt the fornix
23
Q
what are the meninges?
A
- membranes that surround and protect the brain
- cerebrospinal fluid: cushions the brain
- blood brain barrier: protects the brain from exposure to toxins
24
Q
what are the functions of the meninges?
A
- cover and protect CNS
- enclose and protect blood vessels to CNS
- contain and circulate cerebrospinal fluid
25
Q
what is the pia mater?
A
innermost layer, follows the curves of the brain, very delicate, lots of blood vessels
26
Q
what is the arachnoid mater?
A
- superficial to pia mater, looks like spiderwebs.
- subarachnoid space: web-like threads attach arachnoid mater to pia mater. filled with CSF
27
Q
what is the dura mater?
A
- “hard mother” - outermost layer
- two laters of dense fibrous connective tissue (meningeal and periosteal). in some sports, separate to form dural sinuses (drainage for brain) inside
28
Q
what are the dural venous sinuses?
A
- drain blood from the brain and into the internal jugular veins
- major sinuses:
+ superior saggital
+ straight
+ transverse
+ sigmoid
29
Q
what are the ventricles?
A
- fourth interconnected cavities or expansions within brain for circulating CSF
- laternal ventricles (2) communicate with third ventricle via interventricular foramen
- 3rd ventricle drains into 4th ventricle via cerebral aqueduct
30
Q
what is cerebrospinal fluid?
A
- brain and spinal cord “float” in CSF: prevents damaging
- resists compressive forces, cushions against trauma
- feeds brain, removes waste, carries chemical signals
- made in choroid plexuses
- flows through ventricles and into subarachnoid spaces
- absorbed into dural venous spaces
- processes and circulates 500 mL/day
31
Q
what are the arteries of the neck and head?
A
- the right and left common carotid carotid arteries both ascend into the neck and head and divides into internal and external carotid arteries
- internal and external carotid arteries feed the head, brain, and orbital regions
32
Q
describe the blood supply to the brain
A
- internal carotid divides into anterior and middle cerebral arteries
- anterior cerebral artery joins anterior communicating artery
- middle cerebral artery supplies parts of termporal and parietal lobes (~80% of cerebrum)
- right and left vertebral arteries merge to become basilar artery, which divides into posterior cerebral artieries
- these are connected by posterior communicating arteries
33
Q
what is the circle of willis?
A
- anastomosis to protect brain’s bloody supply (allows re-routing of blood)
- formed by posterior cerebral (L,R), posterior communicating (L,R), internal carotid arteries (L,R), anterior cerebral arteries (L,R), anterior communicating arteries (L,R)
