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
what is the pia mater?
innermost layer, follows the curves of the brain, very delicate, lots of blood vessels
26
what is the arachnoid mater?
- superficial to pia mater, looks like spiderwebs.
- subarachnoid space: web-like threads attach arachnoid mater to pia mater. filled with CSF
27
what is the dura mater?
- "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
what are the dural venous sinuses?
- drain blood from the brain and into the internal jugular veins
- major sinuses:
+ superior saggital
+ straight
+ transverse
+ sigmoid
29
what are the ventricles?
- 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
what is cerebrospinal fluid?
- 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
what are the arteries of the neck and head?
- 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
describe the blood supply to the brain
- 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
what is the circle of willis?
- 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)
