Neuroendocrine Systems

Question 1

Function of hypothalamic neurons?

Where do they specifically lead to

Answer 1

Secrete hormones into the blood vessels specifically leading to the pituitary gland

Question 2

Hypothalamic-pituitary-adrenocortical axis

1. General flow?
2. Elevated glucocorticoids lead to ?
3. Other function of ACTH?

Answer 2

1. Hypothalamic neurons release CRH which stimulates ant pituitary to release ACTH into blood which stimulates adrenal cortex to synthesize/secrete glucocorticoids
2. Promotes glycogenolysis and gluconeogenesis (catabolic hormone) - also exerts negative feedback on the axis
3. Acts as a growth factor to induce adrenal hypertrophy

Question 3

1. What part of the skull is located near the pituitary gland?
2. Where in the brain is the pituitary gland located?
3. Where is the pineal gland located in the brain?

Answer 3

1. Located with the sella turcica of the skull base (hypophyseal fossa)
2. Attached to ventral surface of the hypothalamus
3. Deep midline position on the brain surface; protruding from the posterior surface of the thalamus

Question 4

Pituitary gland contains 2 main elements, what are they?

Answer 4

Axon terminals and endocrine cells

Question 5

1. Function of axon terminal of the neuroendocrine neurons of the pituitary gland
2. Endocrine cells of the pituitary gland are regulated by ?

Answer 5

1. Releasing hormones into the capillaries

2. Hormones released by neurons located in the hypothalamus

Question 6

4 major parts of the brain

Answer 6

Cerebrum, cerebellum, brainstem, and spinal cord/roots

Question 7

3 parts of the cerebrum?

Answer 7

Cerebrum/cerebral hemispheres, thalamus, and hypothalamus

Question 8

3 parts of the brain stem in order from superior to inferior

Answer 8

Midbrain, pons, and medulla oblongata

Question 9

3 parts of the anterior pituitary

2 parts of the posterior pituitary

Answer 9

Pars tuberalis, pars intermedia, and pars distalis

Infundibular stalk and pars nervosa

Question 10

1. What does the pars distalis contain?

2. What does pars nervosa contain?

Answer 10

1. Endocrine cells regulated by hypothalamic hormones

2. Axon terminals of hypothalamic neurons

Question 11

Locations of the pars tuberalis?

Answer 11

Surrounds infundibulum

Question 12

Neurohypophyseal system:

1. Some hypothalamic neurons send axon projections where?
2. Here, axon terminals release what, where?
3. What 2 hypothalamic hormones are released this way?

Answer 12

1. Through the infundibulum to the posterior lobe (pars nervosa)
2. Release peptide hormones into systemic circulation via hypophyseal veins
3. Vasopressin (ADH) and oxytocin

Question 13

1. Where are oxytocin neurons located?
2. Where are vasopressin neurons located?
3. What are considered “nuclei” in the hypothalamus

Answer 13

1. Paraventricular nuclei
2. Supraoptic and paraventricular nuclei
3. Clusters of neuron cell bodies

Question 14

What happens to the following in HYPERtonic solutions:

1. Neurons
2. Mechanosensitive ion channels
3. Action potentials
4. ADH

~reverse for hypotonic

Answer 14

1. Neurons shrink
2. Open
3. Action potentials start firing
4. ADH secretion

Question 15

Hypertonic solutions means __ plasma osmolarity

Answer 15

High

Question 16

Central/neurogenic diabetes insipidus

1. Deficiency in?
2. Symptoms
3. Treated by?
4. Causes?

Answer 16

1. ADH synthesis/release by supraoptic and paraventricular neurons
2. Chronic thirst/polydipsia, polyurea/dilute urine, can be fatal is no access to water
3. Hormone replacement
4. Head trauma, neurosurgical complications, tumor/lesions

Question 17

What is nephrogenic diabetes inspidius?

Answer 17

Insensitivity to ADH

Question 18

Syndrome of inappropriate ADH

1. What is it?
2. Symptoms
3. How is it managed
4. Danger in treating it how?
5. Causes?

Answer 18

1. Excess ADH synthesis/release by supraoptic and paraventricular neurons
2. Hyponatremia, range between fatigue and coma/seizures
3. Restricted water intake, ADH antagonist
4. Danger in rapidly “correcting” by giving hypertonic saline - can cause demyelination in pons (potentially fatal)
5. Head trauma, variety of neurological disorders, NSAIDs

Question 19

Neurons of the adenohypophyseal system project to the ___

What do they do here

Answer 19

Median eminence (ventral surface) and release peptide hormones into capillaries of the portal circulation which delivers these hormones to endocrine cells of the anterior pituitary

Question 20

1. Neurohypophyseal system projects into __ lobe, secretion into ___
2. Adenohypophyseal system projects into __ and secretes into __ to __

Answer 20

1. Neurohypophyseal system projects into posterior lobe, secretion into systemic veins
2. Adenohypophyseal system projects into median eminence and secretes into portal veins to anterior pituitary cells

Question 21

Posterior pituitary consists of, and not ?

Answer 21

Consists of capillaries and axon terminals; no endocrine secretory cells

Question 22

Name 6 hormones made and released by the anterior pituitary

Answer 22

TSH, GH, LH, FSH, ACTH and prolactin

Question 23

1. Another name for growth hormone releasing hormone
2. Another name for growth hormone inhibiting hormone
3. What neurotransmitter acts as prolactin inhibiting hormone?

Answer 23

1. Somatotropin
2. Somatostatin
3. Dopamine

Question 24

Function cell type that releases the following hormones:

1. ACTH
2. FSH/LH
3. TSH
4. GH
5. Prolactin
6. Stem cells

Answer 24

1. Corticotropes
2. Gonadotropes
3. Thyrotropes
4. Somatotropes
5. Lactotropes
6. Folliculo-stellate cells

Question 25

1. Which hormones are basophilic (purple) (3) | 2. Which hormones are acidophilic (pink/orange) (2)

Answer 25

1. ACTH, FSH/LH, TSH | 2. GH, prolactin

Question 26

What are neurosecretory granules

Answer 26

Peptide hormones in the axon terminals to be secreted

Question 27

Where are axon terminals positioned? So release of granules is followed by

Answer 27

Close to or adjacent to endothelial cells Transport of hormones across endothelial cells into blood

Question 28

Lobes of the pituitary are derived from? What are the two parts?

Answer 28

Ectoderm Oral ectoderm and neuro ectoderm

Question 29

1. What part is derived from oral ectoderm | 2. Neuro ectoderm?

Answer 29

1. Pars distalis/anterior lobe | 2. Pars nervosa

Question 30

Why does the hypothalamus rarely experience infarct/ischemia? Primary neurological problem in the hypothalamus?

Answer 30

It is highly vascularized Tumor formation

Question 31

Traumatic brain injury can sever?

Answer 31

Infundibulum which would disconnect the hypothalamus and pituitary

Question 32

Two types of pituitary tumors? These tumors grow and expand out of the __, compressing ?

Answer 32

Hypersecretory or non-secretory Sella turcica, compressing cranial nerves or hypothalamus

Question 33

Location of the pineal gland What effect does light exposure have on the pineal gland

Answer 33

At a deep midline position on the brain surface Light exposure inhibits pineal synthesis and secretion of melatonin (darkness= less inhibition of pineal and more melatonin)

Question 34

How light inhibits pineal/melatonin: 1. Light activates what kind of cells. What does these cells do when activated? 2. SCN sends excitatory projections to __ 3. PVN sends excitatory projections to __ 4. These stimulate __ to do what?

Answer 34

1. Retinal ganglion cells; send excitatory projections to a hypothalamic nucleus (suprachiasmatic nucleus) 2. Another hypothalamic nucleus (paraventricular nucleus) 3. Pre-ganglionic sympathetic neurons in T1-T2 spinal cord 4. Post ganglionic sympathetic projections to pineal to inhibit melatonin secretion

Question 35

What pools between the two tails of the pineal gland

Answer 35

CSF