Unit 4 Flashcards
components of the brain:
- cerebrum
- cerebellum
- diencephalon
- brainstem
towards the tail
caudal
towards the nose
rostral
deep groove that runs from rostral to caudal
-separates right from left hemisphere
longitudinal fissure
shallow grooves
sulci
folds of tissues
-allows for increase in surface area
gyri
separates occipital from cerebellum
transverse fissure
“cross talk”
major pathway of communication between the right and left hemisphere
corpus callosum
contains upper motor neurons
gray matter
white because of myelinated axons
white matter
supports and protects the brain:
- cranium
- meninges
- cerebrospinal fluid
- blood brain barrier
provides rigid support
cranium
surrounds and partition
meninges
cushions the brain, flows through ventricles
cerebrospinal fluid
prevents entry of harmful materials
blood brain barrier
three connective tissue layers
-separates and support soft tissue of brain
-enclose and protect blood vessels supplying the brain
-help contain and circulate cerebrospinal fluid
-layers: dura mater, arachnoid mater, pia mater
cranial meninges
helps absorb cerebral spinal fluid
arachnoid granulation
used to drain blood during circulation
dural venous sinus
contains ependymal cells that makes/secretes CSF
lateral ventricle
exit points where CSF will be redirected, enter meningis and circulates around the brain
aperture
clear, colorless liquid surrounding CNS
-circulates in ventricles and subarachnoid space
-functions:
1. buoyancy- reduced brain’s apparent weight by 95%
2. protection- provides a liquid cushion
3. environmental stability- transport of nutrients/wastes and protects against fluctuations
cerebrospinal fluid (CSF)
“classic brain”
the location of conscious thought processes and the origin of all complex intellectual functions
cerebrum
controls motor functions
frontal lobe
paired lobe
function: processing general sensory information
parietal lobe
paired lobe
function: processes auditory information
temporal lobe
processes visual information
occipital lobe
-salience, self awareness and identification
-visceral pain, sculptural beauty
-a “state of union with god”
-hallucinogenic state
-disgust to smells
insular (gustatory) cortex
sends motor signals from the brain to the spinal cord and out to the skeletal muscles
primary motor cortex (precentral gyrus)
control eye movement
frontal eye field (precentral gyrus)
controls motor function of speech
Broca’s area (precentral gyrus)
represents amount of cortex dedicated to motor activity of each body part
homunculus
interpretation of somatic sensory information (touch, pain, temperature, body, position)
primary somatosensory cortex (postcentral gyrus)
processing visual sensations
primary visual cortex (postcentral gyrus)
processing auditory information
primary auditory cortex (postcentral gyrus)
integrate new sensory inputs with memories of past experiences
association areas
ways of brain communication:
- commissural fibers
- association fibers
- projection fibers
links the left and right hemispheres
commissural fibers
allows communication within a particular fiber (ex. one area in the frontal lobe to another area in the frontal lobe)
association fibers
allows communication to pass from the cortex down the brainstem and into spinal cord
projection fibers
two sides of cerebrum exhibit differences in higher order functions
cerebral lateralization
forms posterior part of diencephalon
-contains pineal gland
epithalamus
endocrine gland secreting melatonin
-helps regulate day night cycles, circadian rhythm
pineal gland
“filtration station”
receives signals from all conscious senses except olfaction
thalamus
-master control of the ANS
-regulation of body temperature, hunger, thirst sensations, and sleep wake cycles
-master control of endocrine system; had direct control of pituitary gland
hypothalamus
connects cerebrum, diencephalon, and cerebellum to spinal cord
-contains ascending and descending tracts
-contains autonomic nuclei, nuclei of cranial nerves, and reflex centers
-consists of the midbrain, pons, medulla oblongata
brainstem
first
- redirects your attention to sound
tectum (in the midbrain)
second
-controls respiratory; collection of fibers that innervate muscles in our lungs
pontine respiratory center (in the pons)
last
- communicates with your heart, helps reduce heart rate when it exceeds healthy rate
cardiovascular center (in the medulla oblongata)
last
-rhythmic breathing
medullary respiratory center (in the medulla oblongata)
appearance of a separate structure attached to the bottom of the brain, tucked underneath the cerebral hemispheres
functions:
-receives information on movement from the motor cortex of the cerebrum
-compares intended movement with body position
-send instructions back to the cerebral cortex to continuously adjust and fine tune motor commands
cerebellum
multiple structures that collaboratively process and experience emotions
-cingulate gyrus and fornix: band of tissues that connects rostral and caudal ends
-hippocampus: stores short term memory
-amygdaloid body: process fear response
limbic system
12 pairs that arise from the base of the brain (sensory, motor, mixed)
-exit the cranium through foramina
-lead to muscles and sense organs, located mainly in the head and trunk
cranial nerves
sensory nerve for olfaction (smell)
CN I Olfactory nerve
sensory nerve for vision
CN II Optic nerve
F: most motor (somatic/auto)
O: midbrain
T: rectus/ciliary muscles
P: superior orbital fissure
damage: paralysis/strabimus
CN III Oculomotor
mixed nerve that receives somatic sensation from face; controls muscles involved in chewing
CN V Trigeminal nerve
mixed nerve that controls muscles of facial expression and conducts taste sensations from tongue
CN VII Facial nerve
F: most sensory
O: auditory portions
T: medulla/pons
P: internal acoustic meatus
damage: deafness, nausea, balance
CN VIII Vestibulocochlear nerve
F: mixed
O: thoracic/abpelvic cavity
T: medulla oblongata
P: jugular foramen
damage: loss of voice, GI motility
CN X Vagus nerve
F: most motor
O: C1-C6
T: palate, pharynx
P: jugular foramen
damage: movement of head, neck, shrugging
CN XI Accessory nerve
-structural and functional link between brain and rest of body; sensory input from body, motor commands from brain
-spinal reflexes; responses that do not involve the brain, fast reaction to a stimulus
functions of spinal cord and spinal nerves
part of the spinal cord supplied by each pair of spinal nerves
segment
-8 cervical
-12 thoracic
-5 lumbar
-5 sacral
-1 coccygeal
31 pairs of spinal nerves
via posterior rootlets
-somatic (i.e. tactile receptors, proprioceptors)
-visceral (i.e. baroreceptors, chemoreceptors)
sensory receptors
via anterior rootlets
-visceral; autonomic; (i.e. cardiac muscle, smooth muscle, glands)
-somatic (i.e. skeletal muscle)
effectos
houses neurons that receive incoming sensory information
posterior horn of gray matter
houses large motor neurons that send information out of the spinal cord
anterior horn of gray matter
relays somatic information from muscles
spinocerebellar pathway
ascends towards the brain
sensory pathways
descends from the brain
motor pathways
common pathway characteristics:
- pathways are paired
-cell locations: axons are in spinal cord tracts; cell bodies are in spinal cord gray horns
-each pathway is made of a chain of two or more neurons
Autonomic nervous system
-sudden constriction of small arteries of digits
-triggered by cold or emotional stress
-due to exaggerated local sympathetic response
Raynaud syndrome
controls self regulated action of internal organs and glands
-preganglionic: transmits nerve signals to a ganglionic motor neuron
-ganglionic motor neuron: transmits nerve signals to smooth muscle, cardiac muscle, and glands
-visceral sensory: detects stimuli associated with blood vessels and the viscera
autonomic nervous
controls voluntary movements of skeletal muscles
-motor neuron: transmits nerve signals to skeletal muscle
-sensory neuron: detects stimuli and transmits nerve signals from the special senses, the skin, and proprioreceptors in joints and muscles
somatic nervous
multiple preganglionic neurons synapsing on one ganglionic neuron
neuronal convergence
branches of axon from one preganglionic neuron synapsing with numerous ganglionic neurons
neuronal divergence
integration and command center for autonomic functions; involved in emotions
hypothalamus
contains major ANS reflex centers
brainstem
contains ANS reflex centers for defecation and urination
spinal cord
-brings body to homeostasis in conditions of “rest and digest”
-conserves energy and replenishes nutrient stores
parasympathetic division
-brings body to homeostasis in conditions of “fight of flight”
-increases alertness and metabolic activities
-widespread response
sympathetic division
