2-2-16-Hypothalamic-Pituitary Relationships (Lopez)

Question 1

The relationship between the hypothalamus and the anterior pituitary is ___

The relationship between the hypothalamus and the posterior pituitary is ___

Answer 1

Both neural and hormonal

Neural

Question 2

The anterior pituitary is connected to the hypothalamus by ___

Answer 2

Hypothalamic-hypophysial portal vessels

Question 3

The ___ provide most of the blood supply to the anterior pituitary

Answer 3

hypothalamic-hypophysial portal vessels

Question 4

___ is when you have low or high levels of hormone due to a defect in the peripheral endocrine gland (i.e., thyroid gland)

Answer 4

Primary endocrine disorder

Question 5

___ is when you have low or high levels of hormone due to a defect in the pituitary gland

Answer 5

Secondary endocrine disorder

Question 6

____ is when you have low or high levels of hormone due to a defect in the hypothalamus

Answer 6

Tertiary endocrine disorder

Question 7

In the anterior pituitary,

\_\_\_ releases ACTH
\_\_\_ releases TSH
\_\_\_ releases FSH and LH
\_\_\_ release GH
\_\_\_ releases prolactin

Answer 7

Corticotroph=ACTH
Thyrotroph=TSH
Gonadotroph=FSH and LH
Somatotroph=GH
Lactotroph=Prolactin

Question 8

List the hypothalamic releasing hormone for the secretion of:

a-TSH
B-ACTH
C-LH, FSH
D-GH
E-Prolactin

Answer 8

A-TRH
B-CRH
C-GnRH
D-GHRH
E-PIF (dopamine) or TRH (elevated)

Question 9

The anterior lobe hormones can be separated into these organizational families based on structural and functional homology

Answer 9

• ACTH family
• TSH, FSH, and LH family
• GH and prolactin family

Question 10

___ has melanocyte-stimulating hormone activity

Answer 10

ACTH

Question 11

In ___ disease, ACTH levels increase and skin pigmentation is a symptom of this disorder

Answer 11

Addison

Question 12

ACTH stimulates these 2 zones of the adrenal gland:

Answer 12

Medulla and Cortex

Question 13

The actions from GH result from 2 different effects:

___ has an effect on the target tissues (e.g., skeletal m., liver, adipose)

__ is mediated by the production of somatomedins in the liver (e.g., IGF-1)

Answer 13

Direct

Indirect

Question 14

This particular action/effect from GH causes an increase in [blood glucose] which can cause insulin resistance, decreased glucose uptake and utilization by target tissue, increased lipolysis in adipose. The result is an increase in blood insulin levels.

Answer 14

Diabetogenic effect

Question 15

This particular action of GH leads to an increased uptake of AA’s, stimulation of synthesis of DNA, RNA, and protein, and is mediated by somatomedins.

Answer 15

Increased protein synthesis and organ growth

Question 16

This particular action of GH stimulates synthesis of DNA, RNA, protein, is mediated by somatomedins, and increases metabolism in cartilage-forming cells and chondrocyte prolfieration

Answer 16

Increased linear growth

Question 17

Acromegaly can be a result of what?

Answer 17

GH excess

GH excess is mostly due to a GH-secreting pituitary adenoma

Question 18

What happens if you have GH excess before puberty?

What happens if you have GH excess after puberty?

Answer 18

Gigantism

Increased periosteal bone growth, increased organ size, increased extremities size, coarsening of facial features, insulin resistance, and glucose intolerance

Question 19

___ supports the actions of estrogen and progesterone

Answer 19

Prolactin

Question 20

List 3 actions of prolactin:

Answer 20

Breast development: at puberty –> stimulate proliferation and branching of mammary ducts; during pregnancy –> stimulate growth and development of the mammary alveoli

Lactogenesis–> induce synthesis of lactose, casein, and lipids

Suppression of ovulation –> inhibits synthesis and secretion of GnRH

Question 21

___ is a condition of inadequate or absent production of the anterior pituitary hormones.

Answer 21

Panhypopituitarism

Question 22

What are some causes of hypopituitarism?

Answer 22

Brain damage–> traumatic brain injury, subarachnoid hemorrhage, irradiation, stroke

Pituitary tumors–> adenomas

Non-pituitary tumors–> cranipharyngioma: most common tumor affecting the HP axis in children

Infections–> meningitis, encephalitis, hypophysitis

Infarction–> sheehan syndrome: pituitary in pregancy is enlarged and more vulnerable to infarction

Autoimmune disorders, pituitary hypoplasia or aplasia, genetic or idiopathic causes

Question 23

___ syndrome is when the pituitary gland is enlarged and more vulnerable to infarction during pregnancy

Answer 23

Sheehan

Question 24

Most pituitary tumors are ___ and occur spontaneously

Answer 24

pituitary adenomas

Question 25

___ adenomas release an active hormone in excessive amounts into the bloodstream. The pt usually experience symptoms related to the hormone action in the body

Answer 25

Hormone-producing pituitary

Question 26

A prolactinoma is a tumor that overproduces prolactin and is associated with ____

Answer 26

Hypogonadism and galactorrhea

Question 27

Acromegaly and gigantism are caused by an excess of ___

Answer 27

GH

Question 28

___ is caused by a pituitary tumor stimulating an overproduction of cortisol

Answer 28

Cushings disease

Question 29

The precursor peptide of ADH is ___ The precursor peptide of Oxytocin is ___

Answer 29

Preprossophysin Prepro-oxyphysin

Question 30

___ is the major hormone concerned with the regulation of body fluid

Answer 30

ADH Prepropressophysin to Propressophysin in the hypothalamus --> Goes down hypothalamic-hypophyseal tract (axons of neurons) to the posterior pituitary --> ADH in the posterior pituitary --> when needed, ADH into the bloodstream --> target tissues of kidneys and blood vessel

Question 31

What are triggers of ADH secretion?

Answer 31

- Decreased BP --> cardiac and aortic baroreceptors --> sensory neuron to hypothalamus - Decreased arterial stretch due to low blood volume --> atrial stretch receptors --> sensory neuron to hypothalamus - Increased osmolarity --> hypothalamic osmoreceptors --> interneuron to hypothalamus These all act on hypothalamic neurons that synthesize ADH --> ADH released from posterior pituitary

Question 32

Secretion of ADH is most sensitive to ___ changes. An increased of only 1% of this factor will increased ADH secretion

Answer 32

Osmolarity

Question 33

Aquaporin-2 channels can be found on the ___ membrane and Aquaporin-3 channels can be found on the ___ membrane

Answer 33

Aq2=Apical Aq3=Basolateral

Question 34

Too little water will result in ___ levels of ADH in the bloodstream Too much water will result in ___ levels of ADH in the bloodstream

Answer 34

Increased Decreased

Question 35

When the hypothalamus detects too little water, the pituitary gland releases ADH, the kidneys remove less water from the blood and the urine becomes ___

Answer 35

More concentrated Will also increase thirst levels as plasma [ADH] exceed ~295 mOsm

Question 36

WHen the hypothalamus detects too much water in the blood, the pituitary gland releases less ADH, the kidneys remove more water from blood and the urine becomes ____

Answer 36

More dilute

Question 37

___ is characterized by a lack of an effect of ADH on the renal CD which causes frequent urination and a large volume of dilute urine

Answer 37

Diabetes Insipidus

Question 38

___ results from damage to the pituitary and destruction of the hypothalamus that leads to a lack of or decrease in plasma ADH

Answer 38

Central DI

Question 39

___ is caused by drugs such as lithium or chronic disorders such as polycystic kidney disease and sickle cell anemia. The kidneys are unable to respond to ADH (Increased plasma ADH)

Answer 39

Nephrogenic DI

Question 40

Desmopressin can be used to treat ___ DI

Answer 40

Central DI--> Desmopressin does not work for Nephrogenic DI Desmopressin prevents water excretion

Question 41

Plasma ADH levels are expected to be lower than normal in ___ Plasma ADH levels are expected to be higher than normal in ___

Answer 41

Central DI Nephrogenic DI

Question 42

___ is characterized by excessed ADH secretion, excessive water retention, and/or hypoosmolarity fails to inhibit ADH release

Answer 42

SIADH

Question 43

How do you treat SIADH?

Answer 43

Fluid restriction IV hypertonic saline V2 receptor antagonist Demeclocycline

Question 44

``` Predict anatomic/physiologic changes as a result of pituitary failure and the following hormones: A-GH B-FSH/LH C-TSH D-ACTH E-ADH ```

Answer 44

A-Children: short stature, Adults: no effect B-Infertility, hypogonadism, reduced sperm count in men; Menstrual irregularity in women C-Hypothyroidism D-Loss of pigmentation, hypoadrenalism E-Diabetes insipidus

Question 45

___ is a collection of axons whose cell bodies are located in the hypothalamus

Answer 45

Posterior pituitary --> secretes neuropeptides - Supraoptic nucleus (primarily ADH) - Paraventricular nucleus (primarily oxytocin)

Question 46

SIADH is characterized by ___

Answer 46

Euvolaemia --> Total body water is increased but normal total body sodium