Week 3 Lecture Flashcards
cerebrum
largest and most prominent area of the brain
- has both gray and white matter
- contains cerebral cortex as well as several subcortical structures like the hippocampus, basal ganglia, thalamus, limbic areas, and olfactory bulb
cerebral cortex
part of the cerebrum
- made of neuron cell bodies and their dendrites
- only gray matter
- forms a complete covering of the cerebral hemisphere
- vary in thickness from 2-4 mm
cortex organization
horizontal “laminar” (6-layer) organization and a vertical “columnar” structure
3 types of neurons in the cortex
pyramidal cells, spiny stellate cells, smooth stellate cells
pyramidal cells
excitatory and make excitatory connections with neighboring pyramidal cells
- primary output cells of the cortex
- largest
spiny stellate cells
type of granule neuron (small interneuron) that have a star-like shape formed by dendritic processes radiating from the cell body
- dendrites densely covered in spines to receive high levels of input from other neurons
- receive most of their input from the thalamus and other cortical areas
- form excitatory connections with pyramidal cells
smooth stellate cells
- non-spiny dendrites and are inhibitory neurons
- they receive input from pyramidal cells and form inhibitory (GABAergic) synapses w/ other pyramidal cells
- type of granule neron
laminar organization
the horizontal layers of the cortex
- 6 layers based on cell types and their connections that are generally found in the cortex
- mechanism for sorting its inputs and outputs
- afferents form other cortical areas
- the thalamus distribute themselves in distinctive spatial patterns in specific cortical lamina
molecular layer position and main connections
first layer; dendrites and axons from other layers
small pyramidal layer position, main connection, and alt name
second layer; cortical-cortical connections; external granule layer
medium pyramid layer position, main connections, and alt name
third layer; cortical-cortical connections; external pyramidal layer
granular layer position, main connection, alt name
fourth layer; receives input from thalamus; internal granule layer
large pyramidal layer position, main connections, and alt name
fifth layer; sends outputs to subcortical structures (other than thalamus); internal pyramidal layer
polymorphic position, main connections, and alt name
sixth layer; sends outputs to thalamus; multiform layer
layer 1 composition
mainly dendrites for neurons from deeper layers as well as axons
layers 2 & 3 composition
neurons that project mainly to other areas of the cortex
layer 4 composition
receives the majority of the inputs from the thalamus
layer 5 composition
projects mostly to subcortical structures other than the thalamus like the brainstem, spinal cord, basal ganglia, and the other cortical hemisphere via corpus callosum
layer 6 function
projects mainly to the thalamus
cortical organization
groupings of functionally connected neurons that extend vertically through all layers of the cortex
- commonly referred to as minicolumns
minicolumn
a group of 80-120 neurons arranged together functionally (via their connections and co-dependent activity)
- about 2x10^8 minicolumns in the human cortex
Brodmann map
splits the cortex into over 50 different areas
three parts of cortex
sensory, motor, and association areas (some include limbic as 4th)
sensory areas of the cortex
receive information related to sensation, with different areas corresponding to different senses
postcentral gyrus
contains primary somatosensory cortex and receives info about tactile sensations
motor areas of the cortex
involved in the initiation of movement
- primarily found in the frontal lobe
- include primary motor cortex, premotor cortex, and supplementary motor cortex
association areas of the cortex
spread throughout the cortex and are involved in the integration of information from multiple brain regions
- adds complexity to the perception attained with one sense modality
- facilitates complex cognitive processes
functional areas of the cerebral cortex
- motor cortex
- somatosensory cortex
- primary auditory cortex
- primary visual cortex
- association cortex
- Wernicke’s area
- Broca’s area
what makes up a lobe?
primary areas (receiving sensory input or sending movement commands), and association areas (higher order brain functions like learning, memory, thought, and language)
association areas
- prefrontal association area
- limbic association area
- primary auditory
- secondary auditory
- parieto-occipito-temporal association area
- primary visual
- secondary visual
- secondary somatic
- primary motor
- supplemental and premotor
cerebral lateralization
the two halves of the brain (“hemispheres”) are specialized for specific cognitive functions
what is the effect on identifying objects with a split brain?
without a corpus callosum, information from the right visual hemisphere cannot be sent to the left to generate speech, so subjects with a split brain cannot identify objects to their left
callosal agenesis
partially or totally lacking a corpus callosum
cortical lateralization
having dominance over one side of their body
characteristics of frontal lobe
- contains primary motor cortex
- controls voluntary movements by the body
- largest lobe of the cerebral cortex
- more association cortex for higher-order functions than other lobes
what is the frontal lobe responsible for?
higher cognitive functions such as:
- problem solving
- spontaneity/impulse control
- learning
- working memory
- language production
- motivation
- judgement/risk assessment
- social & sexual behaviors
- planning & decision making
- abstract thought
- emotional regulation
motor association cortex areas
supplemental motor area, premotor area
supplemental motor area function
execution of sequences of movement (attainment of motor skills - in coordination with the cerebellum)
premotor cortex function
planning of movement
where is the prefrontal cortex?
the section of the frontal cortex that lies at the front of the brain, in front of the premotor cortex
prefrontal cortex main function
executive function: the ability to differentiate between conflicting thoughts, to control impulses, to predict future consequences, to plan for a goal, to make decisions, and to problem solve
three subregions of prefrontal cortex
ventromedial PFC, dorsolateral PFC, and orbitofrontal PFC
ventromedial PFC function
connections with brain regions involved in emotional regulation, self-awareness, theory of mind, decision making, and social cognition
self-awareness
understanding our own thoughts and feelings (personality, our values, and our goals) & physical states (interoception)
theory of mind
understanding the thoughts and feelings of others, predicting how others will behave and responding in a socially acceptable way
social cognition
interacting with other people in a socially appropriate way (understanding social cues, reading body language, etc)
dorsolateral PFC function
connections with brain regions involved in working memory, motor control, self-monitoring & control of emotions, attention, cognitive flexibility, problem-solving, impulse control, and planning & decision making
working memory
short-term memory, keeping track of currently relevant info for the task at hand
attention
focusing conscious awareness, supressing distractions, determining what info is important enough for attention, switching attention between different tasks
cognitive flexibility
ability to adapt to new situations and learn new things, deal with change
problem solving
application of logic and reasoning to generate solutions
impulse control
resisting urges and temptations, suppressing behaviors when appropriate
orbitofrontal PFC function
reward anticipation, predicting the outcome of our actions, decision making related to emotional consequences of our choices
what are the circuits that allow executive functions and higher order functions to emerge in the prefrontal cortex?
- central executive network
- default mode network
- salience network
what are the circuits that allow executive functions and higher order functions to emerge in the prefrontal cortex?
- central executive network
- default mode network
- salience network
central executive network function
attention, actively maintaining and manipulating information in working memory, goal-oriented decision making, and cognitive control
- connects prefrontal cortex with parietal cortex & anterior cingulate cortex & others
default mode network function
self-referential processing, social cognition, abstract thought, and introspection
- active when not engaged in a specific task
salience network function
detecting and responding to salient stimuli & plays a role in determining which sensory information is important and which are not
- connects prefrontal cortex with thalamus and insular cortex & others
tri-network model
integrates 3 key intrinsic brain networks that involve the prefrontal cortex: the central executive network, the salience network, and the default mode network, into a single cohesive model underlying normal behavior and cognition
how are the DMN and CEN networks related?
anti-correlated and under control of SN; if a task engages one of them, the salience network inhibits the other
areas of the brain impacted by traumatic brain injury
dorsolateral prefrontal cortex, orbitofrontal cortex, ventromedial prefrontal cortex, anterior temporal lobe
what happened to Phineas Gage?
injury to left frontal lobe changed his personality, lost rational decision making and processing of motion
- retained intellectual, motor, and language functions
where is Broca’s area located
left frontal lobe
what is Broca’s area responsible for
- coordinating cognitive and motor signals to the parts of the body that allow you to produce speech in a clear and fluent manner
- interacting with areas of the cerebral cortex involved in deriving meaning from language, creating sentence structure, and using grammar
Broca’s aphasia
difficulty in producing coherent speech but not with speech comprehension
lobotomy function
remember info and trauma but no associated emotions
symptoms associated with frontal lobe damage
- speech/language impairment
- changes in attention
- changes in working memory
- changes in cognitive control
- changes in emotion processing (difficulty understanding the emotional significance of stimuli or feeling indifferent to upsetting things)
- changes in decision-making (making risky decisions)
- changes in social cognition (difficulty understanding thoughts, feelings, and motivations of others)
- changes in introspection
temporal lobe function
- emotions
- smelling, tasting, perception, memory, understanding music, aggressiveness, and sexual behavior
- language
planum temporale
the superior surface of the temporal lobe - is larger in the left hemisphere in most brains
- includes part of Wernicke’s area, crucial for speech
symptoms of temporal lobe damge
- disturbance of auditory sensation and perception
- disorders of music perception
- disorders of visual perception
- disturbance in the selection of visual and auditory input
- impaired organization and categorization of sensory input
- inability to use contextual information
- impaired long term memory
- altered personality
- altered sexual behavior
symptoms of damage to left temporal lobe
deficits in verbal memory and processing speech sounds
symptoms of damage to right temporal lobe
deficits in nonverbal memory, processing certain aspects of music, and face recognition
temporoparietal junction (TPJ)
brain region associated with reflexive shifts of attention
- shifting attention from one target object to the next
- shifting attention to unexpected or surprising stimuli
ventral frontal cortex (VFC)
working memory
- novel situation = more attentional resources
cause of hemispatial neglect
right hemisphere damage due to strokes, traumatic brain injury, or disease can cause inattention to the left side of the world
Wernicke’s area
the region of the brain important for the comprehension of speech and language development
where is Wernicke’s area located
in the temporal lobe on the left side of the brain and includes the junction between the parietal and temporal lobes
Wernicke’s aphasia
impacts both language comprehension and production of meaningful language
prosopagnosia
inability to recognize faces, including one’s own
- fusiform gyrus usually damaged in these cases
two types of prosopagnosia
developmental prosopagnosia, and acquired prosopagnosia
what causes acquired prospagnosia
damage to the right fusiform gyrus
primary auditory cortex location
temporal lobe
when is the secondary auditory cortex activated?
in response to complex sounds and is involved in the detection of pitch, change in frequency, and identifying the location of sound in an environment
acquired savant syndrome
caused by damage to the anterior portion of the left temporal lobe
parietal lobe function
plays a role in sensations of touch, smell, and tase
- processes sensory and spatial awareness
- key component in eye-hand coordination and arm movement
- contains Wernicke’s area
occipital lobe function and location
controls vision and recognition; at the rear of the brain
where is the primary visual cortex located
occipital lobe
what does damage to the occipital lobe result in
loss of the contralateral visual field
- visual problems (recognizing objects, inability to recognize problems, trouble recognizing written words)
what does bilateral damage to the occipital lobes result in?
cortical blindness
cortical blindness
unaware that they can’t see and offer incorrect descriptions of their surroundings
limbic lobe function
- regulates emotion and memory
- connects the lower and higher brain functions
where does the salience network have nodes in?
insular cortex, prefrontal cortex, and cingulate (limbic) cortex
what are the special senses?
the senses that have specialized organs devoted to them (vision, hearing and balance, smell, taste)
synethesia
a neurological phenomenon in which stimulation of one special senses pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway
characteristic of synesthetic perceptions
- durable and generic
- memorable
- emotional
- involuntary
- incidence
most common types of synesthesia
- grapheme-vision
- sound-vision
- sound-touch
- time units-vision
- vision-flavors
- sound-flavor
- smell-vision
- pain-vision
how many nuclei in basal ganglia
6
how many nuclei in thalamus
50, simplified to 14
how many nuclei in hypothalamus
10
basal ganglia
a group of subcortical nuclei involved in
- motor control
- motor learning
- executive function and behaviors
- emotion
why is basal ganglia a misnomer
“ganglia” is used to refer to clusters of neurons in the PNS, while “nucleus” is used to refer to clusters of neurons in the CNS
what structures are the basal ganglia composed of?
striatum, globus pallidus, subthalamic nuclei, substantia nigra
what is the striatum composed of
caudate nucleus, nucleus acumbens, putamen
what is the globus pallidus composed of
lateral (external), medial (internal)
what is the substantia nigra composed of
compact, reticular
what forms the lentiform nucleus
putamen and globus pallidus
what forms the lentiform nucleus
putamen and globus pallidus
caudate nucleus function
mostly associated with motor function due to its role in Parkinson’s and Huntington’s disease; other functions:
- procedural learning
- associative learning
- planned (cognitive) behaviors
- inhibitory control
- emotional reward system
- part of cortico-basal ganglia-thalamic loop
what section of the brain are you in if you can only see lateral ventricles and the head of the caudate nucleus
rostral section
- no thalamus visible
what section of the brain are you in if you can see the third ventricle, thalamus, middle of caudate, and body of caudate
mid-caudate section
what brain section are you in if the third ventricle, thalamus, both body and tail of caudate nucleus, and hippocampus are visible
caudal sections
internal capsule
- large afferent and efferent white matter tracts
- relay to and from the thalamus to the cerebral cortex
- separates the caudate nucleus from the lentiform nucleus
putamen location and function
- located lateral to the globus pallidus and on the outside of the internal capsule
- regulate movements and influence various types of learning
globus pallidus location and function
- located on the outside of the internal capsule
- involved in the regulation of voluntary movements
nucleus accumbens location and function
- located where the head of the caudate and putamen meet and connect
- involved in motivation, reward or positive behavioral reinforcement, integrates motivation with motor action
striatum
- “stripes”
- striatum = putamen + caudate + nucleus accumbens
- globus pallidus is not part of the striatum
basal ganglia telencephalon structures in the cerebrum DELETE
striatum (caudate, nucleus accumbens, putamen), globus pallidus (GPe (internal/lateral), GPi (internal/medial))
basal ganglia telencephalon structures in the cerebrum
striatum (caudate, nucleus accumbens, putamen), globus pallidus (GPe (internal/lateral), GPi (internal/medial))
basal ganglia structures in the diencephalon
subthalamic nucleus
basal ganglia structures in the midbrain
substantia nigra (compacta, regular)
subthalamic nucleus
functionally part of the basal ganglia, but anatomically within the subthalamus of the diencephalon
- most of the time subthalamic cells are inactive because of the constant inhibition by cells of the external globus pallidus (GPe); if this inhibition is removed, subthalamic neurons have a high level of activity resulting in motor dysfunction (disinhibition)
what neurotransmitter do subthalamic neurons use
excitatory neurotransmitter glutamate
substantia nigra
a nucleus in the brainstem that is part of the basal ganglia
- dark streak that can be seen in unstained brain tissue
why is the substantia nigra dark
dopamine neurons express high levels of neuromelanin
what is the cell death of the substantia nigra associated with
Parkinson’s disease
pars compacta (SNc)
- dorsal part of substantia nigra
- contains densely packed, pigmented modulatory dopaminergic neurons
- serves mainly as an input to the basal ganglia
pars reticulata (SNr)
- nearest to the cerebral peduncle
- contains loosely packed (net-like), non-pigmented inhibitory GABAergic neurons
- serves mainly as output from the basal ganglia
nigrostriatal pathway
formed by the connections between dopamine neurons of the substantia nigra pars compacta (SNcc) and the caudate and putamen (striatum)
- one of the major dopamine pathways in the brain and plays a significant role in the production of movement
four principal input-output loops
- skeletomotor loop
- oculomotor loop
- prefrontal loop
- limbic loop
characteristics of input-output loops
- projections from the cerebral cortex to the basal ganglia and then return back to the cortex by way of the thalamus
- each of the loops originates from multiple cortical regions that have similar general functions
- anatomically distinct: each loop passes through different basal ganglia and thalamic nuclei
- the cortical targets of the loops are separate portions of the frontal lobe
direct pathway
produces wanted movement
- when a movement is desired, a signal to initiate the movement is sent from the cortex to the BG, which frees the thalamus from the inhibitory effects of the BG and allows movement to occur
indirect pathway
prevents unwanted movements
- involves the subthalamic nucleus, leads to the increased suppression of unwanted movements; it is thought that a balance between the two pathways may facilitate smooth movements
what is only visible in anterior/rostral sections
nucleus accumbens
diencephalon
the caudal part of the forebrain that contains the epithalamus, thalamus, hypothalamus, and subthalamus
thalamus
forms the walls of the 3rd ventricle and is involved in these functions:
- relaying sensory and motor signals to and from the cerebral cortex
- regulating consciousness, sleep, and alertness
relay for conscious sensory information to the cortex (ascending tracts)
hypothalamus
an integral part of the endocrine system
- links the nervous system to the body’s hormone system via the pituitary gland
subthalamus
receives afferent connections from the substantia nigra and striatum
- regulates skeletal muscle movements
epithalamus
connects the limbic system to other parts of the brain
- involved in secretion of melatonin by the pineal gland that regulate circadian rhythms/sleep wake cycle
- regulation of motor pathways and emotions
characteristics of the thalamus as a relay for conscious sensory information to the cortex
reciprocal connections with cortical areas forming thalamocortical loops to integrate sensory information and maintaining coherent brain activity
characteristics of the thalamus as regulation of consciousness/alertness/sleep
- recordings and functional imaging of the thalamus in humans and animals show thalamic activity is linked to arousal and wakefulness
- thalamic stimulation can restore or enhance states of consciousness in patients with disorders of consciousness
characteristics of the thalamus as a center for sensory processing
- the thalamus is part of the sensory salience network
- involved in selective attention by filtering sensory inputs to decide what sensory input is important to attend to (focusing attention) and “tuning out” unimportant repetitive stimuli
thalamus functional organization
neurons that relay information through the thalamus that have similar functions are grouped together and travel via the internal capsule to/from the appropriate area of the primary or association cortex
interthalamic adhesion
connects the upper part of the lateral wall of the third ventricle to the thalamus in the other brain hemisphere
internal medullary laminae
divide the thalamus into 4 main groups: medial and anterior nuclei are separated from the lateral and posterior nuclei
intralaminar nuclei
several additional nuclei within the internal medullary laminae that receive input from the reticular formation in the brainstem and project to the striatum and cortex
lateral thalamus main function
integration of sensory information and sends signals to the parietal, temporal, and occipital lobes for further processing
anterior thalamus main function
routing info of attention, memory, and learning
medial thalamus main function
abstract thought and long-term, goal-oriented behavior
intralaminar nuclei main function
maintaining alertness and directing attention to salient sensory events
- receive input from the reticular formation in the brainstem and project to the striatum and cortex
reticular nucleus
sheath that wraps around and forms a capsule around the thalamus
- does not project directly to the cerebral cortex; modulates the information from other nuclei in the thalamus itself
14 efferent connections
- internal medullary laminate
- anterior nucleus - AN
- ventral anterior nucleus - VA
- ventrolateral - VL
- ventral posterolateral nucleus - VPL
- lateral posterior nucleus - LP
- lateral dorsal nucleus - LD
- ventral postereomedial nucleus - VPM
- pulvinar nucleus
- lateral geniculate body
- medial geniculate body
- medial (mediodorsal) nucleus
- intralaminar nuclei
- centromedian nucleus
first efferent connection
internal medullary lamina
second efferent connection
anterior nucleus - AN
third efferent connection
ventral anterior nucleus - VA
fourth efferent connection
ventrolateral - VL
fifth efferent connection
ventral posterolateral nucleus - VPL
sixth efferent connection
lateral posterior nucleus - LP
seventh efferent connection
lateral dorsal nucleus
eighth efferent connection
ventral posteromedial nucleus - VPM
ninth efferent connection
pulvinar nucleus
tenth efferent connection
lateral geniculate body
eleventh efferent connection
medial geniculate body
twelfth efferent connection
medial (mediodorsal) nucleus
thirteenth efferent connection
intralaminar nuclei
fourteenth efferent connection
centromedian nucleu
ventroposterolateral nucleus function
somatic sensation for contralateral body
ventroposteromedial nucleus function
somatic sensation for contralateral face and taste
medial geniculate nucleus function
hearing
lateral geniculate nucleus function
vision
pulvinar nucleus function
visual processing
lateral posterior nucleus function
visual processing
ventrolateral nucleus function
modulation and coordination of movement
ventroanterior nucleus function
initiation and planning of movement
anterior nucleus function
memory storate and emotion
mediodorsal nucleus function
motivation, drive, and emotion
lateral dorsal nucleus function
memory storage and emotion
intralaminar nuclei function
regulation of consciousness/alertness/sleep
hypothalamus location
part of the forebrain below the thalamus
what does the hypothalamus do
- coordinates both the autonomic nervous system and the activity of the pituitary gland
- four Fs: feeding, fighting, fleeing, fucking
- homeostasis
- main visceral center
what does the hypothalamus control as the main visceral control center
- autonomic nervous system (peripheral motor neuron controlling smooth and cardiac muscle and gland secretions)
- heart rate, blood pressure, GI tract, sweat, salivary glands
- emotional drives
- body temp, hunger, thirst
- regulation of sleep-wake centers
- control of endocrine system through pituitary gland
- memory
what hormones does the hypothalamus release to produce a feeling of love
dopamine, oxytocin, vasopressin
how does dopamine relate to love
associated with body’s reward system, making love a desirable feeling
how does oxytocin relate to love
- “love hormone”
- associated with social bonding
how does vasopressin relate to love
involved in social bonding with a partner, sexual motivation, and maternal responses to stress
nuclei of hypothalamus
- paraventricular and supraoptic nuclei
- anterior nucleus
- preoptic area
- suprachiasmatic nucleus
- dorsomedial nucleus
- posterior nucleus
- lateral hypothalamus area
- mammillary body
- ventromedial nucleus
- arcuate nucleus
pituitary gland main function
secrete hormones into bloodstream
what do hormones released from the pituitary gland do
control:
- growth
- blood pressure
- energy metabolism
- temp regulation
- pain relief
- sex organs
- thyroid glands
- pregnancy, childbirth, lactation
anterior lobe of pituitary gland
hormone producing area and the majority of pituitary hormones get produced here; functions as a gland
posterior lobe of pituitary gland
stores and releases hormones produced by certain secretory neurons in the hypothalamus; neural tissue
relationship between hypothalamus and homeostasis
- hypothalamus as a thermostat
- when body temp too high; preoptic and anterior nuclei respond to decrease heat through blood vessel dilation, panting/sweating, suppression of shivering
ventromedial nucleus function
mnemonic: if you want to go to the video music awards in flattering clothes, listen to the ventro medial
controls body’s response to changing levels of glucose, amino acids, hormones, and salts in the body
- regulates hunger
- associated w/ obesity
- aggression/aggression-seeking behaviors
dorsomedial nucleus function
mnemonic: DM initials (DM also stands for diabetes mellitus, which has hunger as an initial symptom)
receives info on feeding regulation, body weight, energy consumption; passes info to regions involved in sleep/wakefulness regulation and corticosteroid secretion
preoptic nucleus function
mnemonic: “love at first sight” references seeing someone in front of your eyes
regulates release of gonadotropic (reproductive) hormones by the anterior pituitary
- thermoregulation
gonadotropins
regulate normal growth, sexual development, and reproductive function
GnRH
gonadotropin releasing hormone; produced in preoptic nucleus and promotes release of other gonadotropins by anterior pituitary
anterior nucleus function
mnemonic: on a hot summer day, how do you face the AC unit? face forward (anterior)
regulates body temp
posterior nucleus function
mnemonic: when it’s cold, you want to shrink back (posterior) into bed
- elevation in blood pressure
- pupillary dilation
- shivering/body heat conservation
lateral hypothalamus function
mnemonic: after you work out your lats, you get hungry
regulates:
- feeding behavior
- arousal
- control of pain perception
- digestive functions
- blood pressure
what does damage to the lateral hypothalamus cause
eating disorders, narcolepsy, and GI disorders
arcuate nucleus function
mnemonic: arcuate and anterior start with a
stimulates hormone release from the anterior pituitary and contains neurosecretory neurons that release its own hormones through the posterior pituitary
- contains receptors for Leptin, insulin, and ghrelin
- involved in feeding behaviors, metabolism, fertility, and cardiovascular regulation
- contains dopaminergic neurons that regulate the release of prolactin
result of damage to arcuate nucleus
obesity
suprachiasmatic nucleus function
mnemonic: master clock
- brain and body’s biological clock
- sets timing of sleep-wake cycle in response to sunlight and darkenss cues
- receives input from retina
- regulates circadian rhythms
paraventricular nucleus and supraoptic nucleus function
mnemonic: if you put the p in the v (of pvn), in 9 months you’ll need oxytocin
release hormones through posterior pituitary and are involved in osmoregulation
- PVN responds to physical and psychological stressors by engaging the HPA stress axis
HPA axix
hypothalamic - pituitary- adrenal axis
first step of HPA axis stress response
PVN detects a stressor and releases corticotropin releasing hormone onto the anterior pituitary
second step of HPA axis stress response
anterior pituitary detects corticotropin releasing hormone (CRH) and secretes adrenocorticotropin hormone (ACTH) into the general bloodstream
third step of HPA axis stress response
ACTH reaches the adrenal glands where the adrenal cortex produces and secretes corticotrophins, cortisol, into the general bloodstream
fourth step of HPA axis stress response
cortisol circulates throughout the body to engage enrgy and immune systems
autonomic nervous system
- rest and digest
- secrete and excrete
- feed and breed
- saves energy
sympathetic nervous system
- fight or flight
- consumes energy
parasympathetic nervous system
counterbalance to the action of the sympathetic nerves
- consists of nerves arising from the brainstem and the lower end of the spinal cord and controls the internal organs, blood vessels, and glands
