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97 Cards in this Set
- Front
- Back
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BEGIN WITH DR. WHITE HYPOTHALAMUS
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yay!
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How much does the limbic system influence the hypothalamus? Give a real life example.
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A LOT! When you are upset, you don't feel like eating at all.
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How do we organize the nuclei in the hypothalamus when classifying them?
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We organize them by regions according to where they are in relation to the optic chiasm.
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Show where the optic chiasm is in relation to the hypothalamus
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What are the different regions?
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Anterior, middle/tuberal, and posterior hypothalamus
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NOW WE TALK ABOUT THE PREOPTIC NUCLEI
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YAY!
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Where are the preoptic nuclei?
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In the anterior region anterior to the optic chiasm (pre=anterior in the brain)
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Show where the preoptic nuclei are.
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What pituitary regulating hormones are released from the preoptic nuclei? Mnemonic?
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the gonadotropic hormones LH and FSH. The amount of these released change with hormone therapy in preop people. PREOP-tic nucleus!
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Hey I thought the arcuate nucleus was the one that released all the AP affecting substances! What gives?
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This is an exception!
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Is the preoptic nucleus the same size in males and females? Why?
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no, males have a much bigger one because they are constant producing gametes.
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Is the size of the preoptic nucleus steady in females?
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No, it varies with our cycle
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What is the name of something that is different in males vs females?
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sexually dimorphic
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WHat happens to our sex potential when there is a lesion in the preoptic nucleus?
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we stop having cycles (amenorrhea) or become impotent.
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What is the non sex role of the preoptic nucleus?
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inducing non REM sleep (non Rapid Eye Movement)
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NOW WE TALK ABOUT TWO VERY WELL KNOWN HYPOTHALAMIC NUCLEI, THE PARAVENTRICULAR AND SUPRAOPTIC NUCLEI
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WHEE
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What region are these two nuclei and where do the neurons there go?
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They are both in the anterior region of the hypothalamus and have the axons of their neurons extend into the PP.
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Show a picture of these nuclei and their neurons.
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What do these nuclei synthesize?
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ADH and oxytocin
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Is one hormone specific to one of these nuclei?
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No, both produce both.
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What would happen to water regulation if there was a lesion in either one of these nuclei?
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You would not get enough ADH so you would have polyuria and polydipsia
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Where exactly are these PP hormones secreted into?
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A venous capillary bed
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Can you show a picture of the hypothalamic nuclei secreting hormones?
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NOW WE TALK ABOUT THE SUPRACHIASMATIC NUCLEUS
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yeeaaahh!
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Show a picture of where the suprachiasmatic nucleus is.
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right above the optic chiasm rather than the optic nerve
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iNPUT of SUPRACHIASMATIC NUCLEUS:
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gets visual input from the retina
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How does it get this visual input?
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the optic tract terminates on this nucleus.
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Mnemonic for suprachiasmatic nucleus function?
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This super charasmatic guy is quite the LOOKER (gets visual input) and even princess Diana knows about it (sends info all over diencephalon)
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OUTPUT of SUPRACHIASMATIC NUCLEUS: where does it send info to?
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It sends this info to other nuclei in the hypothalamus and diencephalon in general
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What does "circadian" mean?
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about a day
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Why does it want to send out the light/dark info to other parts of the diencephalon? What do they control? (be general)
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because those are the nuclei that influence AUTONOMIC VISCERAL FUNCTIONS that need to be regulated by light/dark.
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What do the other nuclei do with the light info given by the suprachiasmatic nucleus?
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the regulate all sorts of things to a circadian rhythm like eating, sleeping, reproduction, and temperature.
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What 3 regions of the brain get direct visual input from the optic nerve?
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1. Lateral genticulate nucleus
2. Pretectal nuclei 3. Suprachiasmatic nucleus |
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Where does the LGN bring visual input to? Deduce?
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the cortex
any thalamic nuclei will always send info to /from the cortex |
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What do the pretectal nuclei do with visual input?
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adjust the pupillary muscles
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NOW WE TALK ABOUT THE ARCUATE NUCLEUS
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WRF
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What region is the arcuate nucleus in?
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The tuberal region
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What is another name for the arcuate nucleus?
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the periventricular nucleus
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NOW WE TALK ABOUT PRODUCTS RELEASED BY THE ARCUATE NUCLEUS INTO THE PORTAL SYSTEM
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YAY
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What is the definition of a portal system?
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veins that go into another capillary bed instead of draining to the heart first
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Are most of the arcuaTe nuclei products stimulatory or inhibitory to the AP?
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stimulatory
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What cells are these inhibitory/stimulatory products influencing in the AP?
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the acidophils and basophils
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What is the best known inhibitory factory in the arcuate nucleus and what does it do?
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dopamine, which blocks prolactin.
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NOW WE TALK ABOUT THE VENTROMEDIAL NUCLEI
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YAY
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Where are the ventromedial nuclei found? Show a picc.
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In the tuberal region of the hypothalamus right on top of the arcuate nuclei
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WHAT IS THE MAIN FUNCTION OF THE VENTROMEDIAL NUCLEI?
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to be a fullness center
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INPUT: What kind of information does the ventromedial nucleus need?
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it needs to know the composition of the blood to tell how much nutrients is there
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OUTPUT: What does the ventromedial nucleus give off?
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Signals to alert you that you are full
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WHAT HAPPENS IF YOU HAVE A LESION OF THE VENTRAL MEDIAL NUCLEUS?
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You will never feel full and will keep on eating and become obese.
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What is the complementary nucleus/zone to the ventromedial nucleus that does the opposite thing?
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The lateral hypothalamic zone
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INPUT: What does the lateral hypothalamic zone use info from?
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The leaky BBB (same as ventromedial zone)
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MNEMONIC for what the lateral hypothalamic zone controls.
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If you have an overactive lateral hypothalamic zone, you will become much more LATERAL!
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DYSFUNCTION: What happens when you have a lesion of the lateral hypothalamic zone?
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You get severe aphagia
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NOW WE TALK ABOUT THE MAMILLARY BODIES!
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YAY!
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FUNCTION: What is different about the function of the mamillary bodies vs all the other hypothalamic nuclei?
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They don't control autonomic visceral functions
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FUNCTION: What brain system is the mamillary body involved in?
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The limbic system aka the papez circuit.
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FUNCTION: Do we know exactly what the mamillary bodies do? How do we know what little we do know?
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No. We can only guess at it from when there is a dysfunction of them.
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DYSFUNCTION: What types of people are prone to getting degeneration of the mamillary bodies? Why?
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Alcoholics and anorexics because they have malnutrition and are prone to getting B1 (thiamine deficiency)
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DYSFUNCTION: What does a B1 deficiency do generally to the brain?
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It makes parts of the brain undergo selective degeneration
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DYSFUNCTION: Which parts of the brain undergo selective degeneration? (4)
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1. Dorsomedial nucleus of thalamus
2. Mamillary Bodies 3. Hippocampus 4. Vermis of cerebellum |
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THALAMUS: What does the dorsomedial mucleus of the thalamus do? (Use Najeeb to remember this)
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Anything in the anterior and medial thalamic areas are highly associated with the limbic system.
It is a limbic relay center. |
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DYSFUNCTION: What are two general symptoms of someone with alcoholism?
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1. Memory loss
2. Loss of balance |
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DYSFUNCTION: Can you categorize each degenerated brain area into the two main symptoms of B1 deficiency?
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1. Memory loss
Limbic system: Hippocampus, dorsomedial thalamus, mamillary bodies 2. Loss of coordination Vermis of cerebellum |
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DYSFUNCTION: Exactly what part of the vermis is degenerated and is this short term or long term?
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The purkinjie cell layer and this happens in short term (straight line test), but can be more permanent in long term.
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NOW WE TALK ABOUT THE HYPOTHALAMIC NUCLEI THAT REGULATE AUTONOMIC NEURONS (S AND PS)
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40 MINUTES INTO THE LECTURE
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ANATOMY: Which nucleus regulates the PS and which regulates the S nervous system? What zones are they in?
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Anterior hypothalamus: PS in the anterior zone
Posterior hypothalamus: S in the posterior zone |
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MNEMONIC: How do you remember which zone controls which autonomic functions?
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If you stare at someone's posterior, you will get very excited and your sympathetic nervous system will activate.
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ANATOMY: How exactly do the anterior and posterior hypothalamus activate the different components of the autonomic system?
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They will actually project down and activate them in the brainstem and spinal cord directly.
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ANATOMY: Where are the neurons for PS vs S systems located?
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PS: mostly in brainstem and sacrum
S: T1-L2 |
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FUNCTION: What kind of change in body temperature is the POSTERIOR hypothalamic zone most sensitive to and what is it's response?
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it senses decreases in heat and will close pores and skin blood vessels and trigger shivering.
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MNEMONIC: How do I use cario exercise physiology to remember what the sympathetic nervous system does in response to heat?
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At first when we exercise, there is sympathetic stimulation everywhere and we are cold. WHen heat rises, we can selectively shut off sympthetics to the skin to sweat and lose heat
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DYSFUNCTION: What pathology do we get when there is a lesion of the posterior hypothalamic zone?
Mnemonic: How can I use wakefulness/sleepiness in certain temperatures to remember if the S or PS respond to heat/cold? |
hypothermia
We are more alert in cold and lazy in heat so the sympathetics are being activated in the cold. |
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DYSFUNCTION: WHat kind of creaures would we be like if we didn't have a posterior hpothalamic zone? Why?
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cold blooded creatures like lizards because we wouldn't be able to warm ourselves up in response to colder weather
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FUNCTION: What kind of change in body temperature is the anterior hypothalamic zone most sensitive to and what is it's response?
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rises in body temperature in which is will open up pores and stimulate sweat to dissipate heat.
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DYSFUNCTION: What pathology do we get when there is a lesion of the anterior hypothalamic zone?
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hyperthermia
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ANATOMY: Do the autonomic neurons projecting to the spinal cord run ipsilateral or contralalteral?
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Ipsilateral.
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ANATOMY: Do the PS and S controlling neurons in the CNS run in a predictable bundle/tract?
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sympathetics do, but we don't know about the PS's yet
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DYSFUNCTION: What happens if we get a lesion of the sympathetic pathway anywhere above T1?
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Horner's syndrome on the ipsilateral side
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NOW WE TALK ABOUT THE EPITHALAMUS!
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WOOT! SOMETHING I KNOW ABOUT.
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ANATOMY: What is included in the epithalamus and what structures is it behind and above?
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Pineal body and habenular nuclei
It is above the superior colliculus and right behind the hypothalamus |
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DYSFUNCTION: If we get a tumor of the pineal body, what structure will likely be compressed?
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The upper midbrain and pretectal area.
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DYSFUNCTION: What syndrome would compression of the pretectal area produce? What are the sx?
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Parinaud's syndrome where there is an
1. impairment of conjugate vertical gaze 2. suppressed pupillary reflex to light 3. Raised ICP |
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DYSFUNCTION: Why would there be pupillary light reflex suppression in Perinaud's Syndrome?
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because the pretetal nuclei and the edinget westphal PS nuclei controlling cilliary muscles are dysfunctional.
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DYSFUNCTION: Why would there be impairment of vertical gaze in Perinaud's Syndrome? What does that even mean?
Mnemonic with dogs? |
It means you can look up or down with both eyes without moving your head. The superior colliculi are responsible for this.
Supposedly dogs can't do this so they have smaller superior colliculi. (just roll with this) |
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DYSFUNCTION: Why would there be raised ICP in Perinaud's Syndrome?
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It may compress the cerebral aqueduct and cause raised ICP.
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DYSFUNCTION: What happens to young boys if they have a cyst in their pineal gland?
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They will develop precocioous puberty
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DYSFUNCTION: What other nuclei is probably being influenced by the pineal cyst in causing precocious puberty? Do we know how this happens?
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The Preptic nuclei (gonadotropin hormones)
This is probably through one of the other functions of the pineal gland that is not well understood. (not melatonin) |
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FUNCTION: Do we know what the habenular nuclei do?
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Not really
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HISTOLOGY: What cells are found in the pineal gland? (multiple cells) Are they neurons?
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Pinealocytes (secrette hormones), glial cells, but NO NEURONS!
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FUNCTION: What hormoneSSSS (plural) does the pineal gland secrete?
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melatonin, serotonin, and CCK
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FUNCTION: How does the pineal gland know when it is dark so that it can release melatonin?
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It gets input from the suprachiasmatic nucleus (that looker!)
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FUNCTION: Do we know everything about how the pineal gland functions? What do we know?
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No, we mainly know about it's role in circadian regulation
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NOW WE TALK ABOUT THE SUBTHALAMUS
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GOING BACK TO MY TERRITORY AGAIN!
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FUNCTION: the subthalamus is part of the diencephalon. What other system is it also a part of?
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The basal ganglia.
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DYSFUNCTION: What kind of movement do we get when there is a lesion to the subthalamus? How would you describe this? Mnemonic?
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Ballismus or hemiballismus (ballistic like flinging stuff so flingling limb movements)
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SUMMARY: Can you sum up the main functions of each of the following parts of the diencephalon discussed in this lecture?
1. THALAMUS 2. HYPOTHALAMUS: 3. EPITHALAMUS 4. SUBTHALAMUS |
1. THALAMUS: relay center to the cortex
2. HYPOTHALAMUS: regulates autonomic visceral functions, but is not limited to that 3. EPITHALAMUS: circadian rhythm 4. SUBTHALAMUS: part of the basal ganglia helping with the indirect pathway |
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MNEMONIC: How can you remember what structure is compressed in Parinaud's syndrome?
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The superior colliculi. It is a PAIR of eyes IN the AUDitory colliculi.
PAIR-IN-AUD! |
