TEST 4 BRAIN ANAT & PHYS Flashcards
What divides the L hemisphere from the R hemisphere of the brain?
Longitudinal fissure
Wide, deep separation of the brain tissue
Fissure
Infolding on the surface of the brain
Sulcus (sulce)
Upfolding on surface of the brain
Gyrus (gyri)
Separates the frontal lobe from the parietal lobe on each side of the brain
Central sulcus
Locations of the primary MOTOR cortices on each side of the brain
Precentral gyrus (gyri)
Location of the primary SENSORY cortices on each side of the brain
Postcentral gyrus
What divides the parietal and occipital lobes from each other?
Division based off of function, NO anatomic demarcation that separates them
Separates temporal lobe from the frontal lobe and the temporal lobe from most of the parietal lobe
Lateral Fissure
This is below the hemispheres of the brain, composed of tracts. It connects the R and L hemispheres so that each side of the brain knows what the other side is doing
Corpus callosum
Just the below the corpus callosum is the lateral ________ where CSF is.
Lateral ventricle
Most inferior part of the brain stem
Medulla
The opening below the medulla that separates most inferior brainstem to most superior SC
Foramen magnum.
What 3 structures compose the Brainstem?
Midbrain (mesencephalon)
Pons
Medulla oblongota
What 2 structures compose the Diencephalon
Thalamus
Hypothalamus
There are both ascending and descending pathways that MUST pass through the medulla to get info to higher brain centers and back to SC/skeletal muscle. TRUE/FALSE
TRUE
Where are the decussation of the pyramids located
Anterior/inferior surface of the medulla
This is where descending motor pathways cross over to the other side of the SC. Responsible for L side of brain controlling R side of body visversa
Decussation of the pyramids
About _____% of descending motor pathways will cross over to the other side of the SC when they get to the decussation of the pyramids
85%
Located in the medulla, recieve input from the inner ear and play a role in maintaining balance
Olives
Where are the inspiratory and expiratory centers located in the brainstem?
Medulla
Nerve cell bodies (nuclei) located in the medulla
CN IX. glossopharyngeal X. vagus XI. Spinal accessory XII. Hypoglossal
These nuclei are related to CN IX and X, and play a role in the baroreceptor reflex.
Nucleus Solitarius
Nucleus Ambiguus
Where do we find the baroreceptors for CN 9 and 10?
IX (glossopharyngeal): carotid sinuses; bifurcation of the internal carotids
X (vagus): Aortic arch
What activates the baroreceptors?
Increase in blood pressure
Increase in BP = activated baroreceptors = increase in ________transmission through the __________ portions of CN IX and X.
Increase in IMPULSE tx through the SENSORY portions of IX and X
As the impulses transmission approaches medulla, the pathways come together to form _________ and enter nucleus _________.
Tractus solitarius and enters nucleus solitarius
When nucleus solitarius activated, sends message to _________ which is the CV output center.
Nucleus ambiguus
When nucleus ambiguus activated, it excites what receptors?
Central Alpha II receptors
When central alpha II receptors are activated, it decreases ________ outflow and increases ________ outflow.
Decreases SNS outflow and increases PNS outflow
What happens with PNS outflow to help bring BP down?
HR decreases
Decreased strength of contraction
Blood vessels dilate
If we have low BP, the baroreceptors and nuclei are NOT excited and we end up having increased ________ outflow.
How does this increase BP?
Increases SNS outflow
HR increases, Contractility increases, and blood vessels constrict
These 3 structures are involved in modulating pain transmission and help decrease the intensity of pain.
- Raphe magnus nucleus
- Reticularis paragigantocellularis
- Periaquaductal gray matter
What type of NT and receptors are abundant at the sites that modulate pain tx?
Endogenous opioids and MU, Kappa, Alpha receptors
All of these autonomic reflexes are mediated through nuclei in the medulla. (5)
CV/vasomotor center Swallowing Vomiting Coughing Sneezing
This is located in the 4th ventricle and highly related to N/V
Chemoreceptors trigger zone (CTZ)
The CTZ is located OUTSIDE/INSIDE the BBB and comes DIRECTLY/INDIRECTLY in contact with CSF.
CTZ is OUTSIDE the bbb
DIRECTLY in contact with CSF
Any noxious stimuli to the CTZ leads to DECREASED N/V. TRUE/FALSE
FALSE
Any noxious stimuli leads to N/V
What type of drugs are directed at receptors in the CTZ?
Antiemetics
There are only ascending pathways that cross through the Pons. TRUE/FALSE
FALSE
Both ascending and descending tracts pass through the pons.
Tracts that connect the cerebrum to the cerebellum are here
Pons
Coordination of what two parts of the brain lead to coordinated skeletal muscle movement
Cerebrum and cerebellum
This has to do with conscious regulation of skeletal muscle movement
Cerebrum
Has to do with unconscious coordination of skeletal muscle movement
Cerebellum
Nuclei for which CN are located in the pons?
V: trigeminal
VI: abducens
VII: facial
VIII: vestibulocochlear
The pneumotaxic respiratory center is located here
Pons
Site for NE synthesis and secretion in the pons
Locus ceruleus
Locus cereleus is part of what system that has to do with awakeness, alertness, attentiveness.
Reticular activating system (RAS)
Midbrain contains the nuclei for what CN?
III: oculomotor
IV: trochlear
Nuclei for CN III - XII are all located in what structure?
Brainstem
Midbrain is divided into that two structures? (Roof and floor of midbrain)
Tectum (roof)
Tegmentum (floor)
What are the 4 twin bodies located in the tectum of the midbrain?
Corpora quadrigemina
- 2 superior colliculi
- 2 inferior colliculi
This part of the corpora quadrigemina receives sound impulses from the inner ear
Inferior colliculi
Where does the inferior colliculi send sound impulses after received
Superior colliculi
Part of the corpora quadrigemina that is for visual tracking of an object. Uses impulses from eyes, skin and cerebrum.
The 2 superior colliculi
Who is an example of someone who has very well developed superior colliculi?
MLB hitter
ASCENDING tracts pass through here after passing through the medulla an pons, before they get to the cerebrum.
Tegmentum (floor of midbrain)
This is the origin of the rubrospinal tract, has to do with unconscious coordination of movements.
Red nuclei
What animal has highly developed red nuclei?
Red nuclei
Origin of the nigrostriatal tract, part of the basal nuclei
Substantia Nigra
Red nuclei/rubrospinal tract, substantia nigra are located where in the brain?
Tegmentum of the midbrain
These are descending tracts that connect the cerebrum to the SC, located in the midbrain.
Cerebral peduncles
The nuclei of the RAS are scattered widely throughout the brainstem. TRUE/FALSE
TRUE
RAS receives impulses from nerves that innervated the face. (Eyes, skin, ears, nose, etc.) TRUE/FALSE
TRUE
These two things make up the medullary respiratory center
Medullary inspiratory center
Medullary expiratory center
Part of control of ventilation in the pons of the brainstem
Pontine pneumotaxic center
The cells that compose the medullary insp center SPONTANEOUSLY generate AP or are spontaneously active. TRUE/FALSE
TRUE
MIC sends impulse to the phrenic nerve that innervates the ___________ creating longitudinal distance in the lungs.
Diaphragm
MIC also synapses with intercostal nerves that innervates ___________ intercostal muscles and pull the ribcage _______ and _______ creating anterior and posterior size of the lungs.
Intercostal nerves activate EXTERNAL intercostal muscles that pull the ribcage UP and OUT.
As the size of the lungs increases, the volume of the lungs increases, which INCREASES/DECREASES intrapulmonary pressure
Decreases intrapulmonary pressure
When does air enter the lungs?
When does air movement stop?
When intrapulmonary pressure is less than atmospheric pressure, goes with gradient
Stops when pressure equilibrates.
During normal quiet breathing expiration is an active process. TRUE/FALSE
FALSE
It is a passive process
The MIC has a collateral axon to the ________ that sends impulses down to MIC to stop sending AP
Pontine pneumotaxic center
When MIC is not activated, then diaphragm is no longer activated, so the muscle does what to decrease the longitudinal size of the lungs
Domes up/relaxes
MIC not activated, so external intercostals are not active, so they do what to decrease ant/post size of lungs
Pulled down and in
As lung size decreases, intrapulmonary pressure DECREASES/INCREASES.
INCREASES
When does air exit the lungs, according to pressures?
When intrapulmonary pressure exceeds atmospheric pressure
This is ONLY active during a forceful expiration; in the medullary respiratory center.
Medullary expiratory center
Ex) bday candles
MEC synapses with the intercostal nerves that innervate the __________ intercostal muscles
Internal intercostal muscles
When internal intercostal muscles are activated what happens to the ribs?
Causes what to happen to the size and intrapulmonary pressure?
Pulled further down and further in
which decreases size of the lungs, and increases the intrapulmonary pressure to exert a forceful exp
We can increase/decrease ventilation by higher brain centers, just by thinking about it. TRUE/FALSE
TRUE
Located in the medulla, they monitor the pH of the CSF; indirectly measures CO2 levels.
Central medullary chemoreceptors
An INCREASE/DECREASE in CO2 causes excitation of central medullary chemoreceptors
INCREASE
What happens to ventilation and pH when central medullary chemoreceptors are excited?
Increases rate and depth of ventilation, which blows off CO2 and decreases CO2 content and the pH of the CSF and receptors are no longer excited.
Where are peripheral chemoreceptors located; primarily monitor the PO2 of blood.
Bifurcation of the carotids and aortic arch
What excites peripheral chemoreceptors?
When PO2 gets below ~50-60
Peripheral chemoreceptors send a message to the MIC that INCREASES/DECREASES rate and depth of ventilation.
INCREASES
This reflex has to do with stretch receptors in the lungs that prevent overinflation of the lungs
Hering-brewer reflex
Increased muscle activity and Pain both INCREASE/DECREASE rate/depth of ventilation
INCREASE
Largest portion of the diencephalon
Thalamus
4 components of the diencephalon
Thalamus
Subthalamus
Epithalamus
Hypothalamus
Located between the 2 lobes of the thalamus
3rd ventricle of the brain
Why is the thalamus considered the “relay center”?
Where almost all sensory input arrives/stops before information is sent to higher brain centers
The thalamus INTERPRETS the sensory input that arrives. TRUE/FALSE.
FALSE
It just tells which area of the brain the sensation should be sent to, it does not interpret it.
Located on the thalamus, receive input form CN II (optic) visual pathways before transferred to higher brain centers.
Lateral geniculate bodies
Also located on the thalamus, and receive CN VIII (vestibulocochlear) auditory pathways before transferred to higher brain centers
Medial geniculate bodies
The thalamus plays a minor role in our UNCONSCIOUS response to pain and suffering. TRUE/FALSE
FALSE.
Plays a MAJOR role in our response to pain and suffering.
The subthalamus is one component of the ________ nuclei
Basal nuclei
What two structures compose the epithalamus
Habenular nucleus
Pineal body
Receives lots of input from CN I (olefactory) fibers, and lays a role in the limbic system; especially our emotional/visceral gut response to odors.
Habenular nucleus of the epithalamus
Where melatonin is secreted from
Pineal body
Melatonin is produced during ________ and suppressed during ______. Can be highly associated with ________.
Produced in darkness, suppressed in light.
Can be associated with depression.
Main fxn of the hypothalamus
Regulate the activity of the pituitary gland
How is the hyothalamus connected to the pituitary gland?
Infundibulum (stalk)
Connects the hypothalamus to the anterior pituitary
Hypothalamohypophyseal portal system
Two capillary networks connected by a vein.
Portal system
Another name for anterior pituitary
Adenohypophysis
Hypothamohypophyseal portal system allows _______ to be transported from hypothalamus to the anterior pituitary to regulate synthesis and secretion of the ant pit ______.
Hormones; hormones
Growth hormone releasing hormone produces what hormone from the anterior pituitary
Growth hormone synthesis and secretion
Secreted from the hypothalamus and causes inhibition of growth hormone syn/sec from the ant pit
Growth hormone inhibiting hormone or somatostatin
Thyroid stimulating hormone releasing hormone = what hormone from the ant pit
Thyroid stimulating hormone synthesis and secretion
TSH stimulates receptors in the thyroid to produce what?
T3 and T4
Adrenocorticotropic hormone releasing hormone = syn/sec of what hormone in the ant pit
ACTH
Where are the primary receptors for ACTH, and what is released from this area.
Adrenal cortex
Primarily cortisol, also aldosterone and some androgens
What 2 hormones are syn/sec in response to gonadotrophin releasing hormone from the hypothalamus
Follicle stimulating hormone (FSH)
Luteinizing hormone (LH)
Target cell receptors in women for FSH and LH?
Men?
What hormones does it regulate in women/men?
Women: ovaries, regulates estrogen/progesterone
Men: testes, regulates testosterone production
Causes synthesis and secretion of prolactin from the ant pit
Prolactin releasing hormone
Target cell receptors for prolactin in women is in the _______, and causes milk ________.
Breast
Milk production
Secreted from the hypothalamus and inhibits syn/sec of prolactin from the ant pit
Prolactin inhibiting hormone
As the circulating ant pit hormones INCREASE/DECREASE, there is feedback to the hypothalamus to alter its output.
INCREASE
