Test 2: Pituitary and Hypothalamus Flashcards
Diabetes insipidus can be caused by?
Treatment?
Damage to stalk of the pituitary from trauma
treat with synthetic ADH (vasopressin)
Suprachiasmatic nucleus
- Function
- Lesion here causes
- Circadian rhythm
- loss of circadian rhythm
Supraoptic/paraventricular nuclei
- Function
- Lesion results in
- Increased blood volume, pressure and metabolism
- Diabetes insipidus, treat with ADH
Lateral hypothalamic nucleus
- Function
- Lesion results in
- Increased feeding
- decreased feeding
To become more lateral (wide) activate the lateral hypothalamus
Ventromedial nucleus
- Function
- Lesion results in
- Decreased feeding
- increased feeding
Dorsomedial nucleus
- Function
- Lesion results in
- Sham rage
- Decreaesd aggression and feeding
Mamillary body
- Function
- Lesion results in
- Unknown fx
- short term memory isn’t processed into long term memroy= **anterograde amnesia **
This is associated with thiamine deficiency and alcoholism.
Korsakoff syndrome= degradation of mammillary bodies (anterograde amnesia), hippocampus, and dorsomedial thalamic nucleus. Fornix carries projections from hippocampus to hypothalamus.
You’re having a conversation with the patient. He has been in the hospital for 3 days. You ask him what he did yesterday, and he tells you he went to the park. What’s going on?
CONFABULATION! patient doesn’t remember so his brain fills in the gaps.
Damage to hypothalamospinal fibers
Horner’s syndrome on ipsilateral side. This is seriosuly in every chapter we’ve covered. I’d make sure you understand it.
**Polyuria, polydipsia, are characteristic of ____ which is caused by ____. _____ is responsible for those symptoms. **
Characteristic of diabetes insipidus caused by damage to the **supraoptic or paraventricular nucleus or **supraoptic hypophysial tract. **LOW ADH causes the symptoms.
When does the ____ realease ADH?
The posterior pituitary releases ADH in response to hypovolemia.
Bitemporal hemianopia can be caused by?
Pituitary tumor. A pituitary tumor can damage the optic nerve, chiasm or tract.
How are pituitary tumors characterized? Names some examples.
- Secreting tumors- make too much hormones= prolactin. non secretory tumors= undetected until size compresses something.
- Size: Microadenomas <1cm vs Macroadenomas>1cm
- Invasiveness- can invade dura or sphenoid bone
Visual disturbances and headaches are common in patients with?
**Non secreteing ** pituitary tumor that compress on optic chiasm or hypothalamus.
Gigantism
- excess growth hormone BEFORE closure of epiphseal plates
- extremely tall, muscles have a lot of CT instead of muscles
Acromegaly
- Cause
- Sx
- secondary problems.
- excess GH **AFTER **closure of epiphyseal plates
- enlargement of digits, elongation of face, malocclusion of jaw and gaps in lower teeth. Bulbous nose, thick lips, large hands and feet. Mastoid and front sinuses bulge.
- 2o= cardiomegaly leading to cardiac failure, hypertension, DM
Thyrotropin tumors
abnormal CV function and tremor. Headaches, visual distrubrnaces and parasellar CN dysfunction in the following order: abducens, oculomotor, trochlear.
What cranial nerves can be compromised from pituituary growth?
Parasellar cranial nerves= 3,4,6
Medial–> lateral: abducens, oculomotor, trochlear.
Cushings disease
- CRH or ACTH cause overproduction of cortisol.
- Sx: truncal obesity, moon faces, facial hisutism (hair), buffulo hump, purple to violet stria (compared to pale white)
- Hyperpigmentation, easy bruising, hypertension, osteopenia, emotional lability
Hyperprolactinemia
- What is it
- Pathological?
- associated sx?
- Galactorrhea= milk production
- Normal during pregnancy.
- Can also cause amenorrhea (which can be occur independently of this from low body fat)
Pituitary tumors account for ____ of brain tumors.
12%. When found later in life, it’s usually an accident and they weren’t doing anything bad.
- What is a pituitary pathway that is tonically inhibited?
- How is that inhibition reversed?
- Prolactin production is tonically inhibited by **prolactin inhibiting factor. **Inhibition stops during pregnancy, birth and nursing.
- Suckling reflex stimulates PRF (Prolactin releasing factor) and prolactin production.
Differential diagnosis for hyperprolactinemia.
- hypothyroidism
- drug use
- In men it is accompanied by decreased libido, impotency or infertility
Most commmon pathologic cause of infertility in men?
PRF hypersecretory tumor
Excessive FSH affect? What are the symptoms?
No effect in men or post-menopausal women
Exessive FSH in pre-men= shut down menstrual cycle.
Excessive LH secretion
precocious puberty in males and disruption of normal period in females
Most common symptoms of gonadotroph ademonas that raise attention?
visual impairment, headaches and sometimes diplopia
**FROM MASS EFFECT= **compression of CN III from lateral extension of tumor.
Where should i put a lesion to make someone realize what it’s like to be always cold? (body temperature decrease, inhibition of symp NS)
lesion in caudolateral hypothalamus
Aortic arch and carotid sinus are considered _______ receptors. They sense _______ . What is the reflex and pathway?
**Baroreceptor reflex, **they are EXTRINSIC receptors.
low BP==> info to neurons of solitary nucleus==>activation of dorsal vagal nucleus ==> terminal ganglia of hear to increaseforce of contraction and HR
(opposite effect if high BP)
Where does the solitary nucleus project to indirectly affect dorsal vagal nucleus?
paraventricular, dorsomedial and lateral hypothalamic nuclei which project to dorsal vagal nucleus.
I just found out we have our second interview on Thursday, making my blood boil. What does my body do?
Neurons in rostral hypothalamus respond to hot blood==> sweating and cutaneous vasodilation.
I’m in the anatomy lab= SUPER EFFING COLD. What’s my body doing?
Cold blood activates **caudal hypothalamus==> **cutaneous vasoconstriction (heat conservation) and shivering (heat production)
Vasocontriction mediate by autonomic pathways
Shivering= **reticulospinal pathways. **
- What’s different about the water balance reflex compared to baroreceptor?
- Where are the “sensory/afferent” neurons? Efferent limb?
- **Neurohumoral= **efferent part is hormone (ADH) rather than neural.
- Osmolarity sensed by **osmolartiy sensitive neurons ** in the **anterior hypothalamus ** near the preoptic and paraventricular nuclei===> neurons IN the preoptic and paraventricular nucleus neurons make ADH (in response to ant pituitary)
- Low blood osmolarity causes?
- High blood osmolarity causes?
- Low osmolarity= Less ADH= decreased renal reabsorption in collecting tubules
- High osmolarity= high ADH= increase reabosorption in collecting tubules.
What hormone when oversecreted can cause **hyponatrimia? **
**ADH (ADH secreting tumor) **
Sx of hyperthyroidisms? Causes?
Caused by excess TSH= increased T3/T4==> **sweating, insomina, tremor, weight loss, heat sensitivity. **
What should I do to get insomnia so I can maybe pass this damn test?
Lesion in the ventrolateral preoptic nucleus= less inhibition to tuberomamillary nucleus= HISTAMINE OVERPRODUCTION.
remember **anti histamines ** make you sleeepppyyy
Why does this person keep falling asleep mid sentence?
narcolepsy
Orexin neurons in lateral hypothalamus STIMULATES tuberommammilary nucleus= Histamine release.
Lesion to orexin neurons= less histamine= sleepiness.
What sort of lesion would inhibit pituitary function?
Lesion in hypothalamus blocks transport of endocrine factors==> adverse affect on pituitary fx.
