endcrine

Question 1

hypothalamus and pituitary gland

Answer 1

Hypothalamus – a region of the brain that contains centers for behavioral drives and plays a key role in homeostasis
Integration between nervous and endocrine systems
Hypothalamus controls activity of the Pituitary Gland (a lima-bean shaped structure that extends downward from the brain).
Releases hormones that act on anterior pituitary
Produces hormones stored & released from posterior pituitary

Question 2

posterior pituitary

Answer 2

The posterior pituitary is the storage and release site for two neurohormones: oxytocin and vasopressin.
When a stimulus reaches the hypothalamus, an electrical signal passes from the neuron cell body in the hypothalamus to the distant end of the cell in the posterior pituitary.
Depending on the stimulus, two posterior pituitary neurohormones are released into the blood:
Oxytocin – In women, controls the ejection of milk during breast-feeding and contractions of the uterus during labor and delivery.
Vasopressin (also known as antidiuretic hormone or ADH) acts on the kidneys to regulate water balance in the body.

Question 3

anterior pituitary(adenohypophysis)

Answer 3

The anterior pituitary is a true endocrine gland that secretes 6 classic hormones.
Trophic Hormones – hormones that act on other endocrine glands to stimulate growth, development and release of hormones

1. prolactin PRL
2. Growth Hormone GH
3. Thyrotropin TSH (thyroid sitmulating hormone
4. Adrenocorticotropin (ACTH)
5. Luteinizing Hormone Lh
6. Follicle-stimulating hormone FSH

Question 4

what are the gonadotrophs

Answer 4

LHand FSH

Question 5

PRF

Answer 5

PRFs prolactin releasing factor released by hypothalamus.

Question 6

what is PIF

Answer 6

PIF (dopamine) prolactin inhibiting factor

Question 7

what is TRH

Answer 7

thyrotropin releasing hormone released by hypothalamus, bind to thyroid gland which then release thyroid hormones

Question 8

what is CRH

Answer 8

corticotropin releasing hormone, to ACTH, which stimulates adrenal cortex which releases cortisol

Question 9

GHRH

Answer 9

growth homrone releasing hormone, stimulates liver, releases IGF

Question 10

what is somatostatin

Answer 10

inhibits Growth hormone

Question 11

gnRH

Answer 11

gonadotropin releasing hormone, to fsh and lh, targets endocrien cells of gonads, which then release androgens estrogens and progesterone, which stimulate germ cells of the gonads.

Question 12

Pineal Gland

Answer 12

A pea-sized structure buried deep in the brain.
Secretes melatonin – “the darkness hormone” secreted at night as we sleep
Regulates circadian rhythm
Linked to sexual function, the onset of puberty, and depression in the darker winter months.

Question 13

adrenal glands

Answer 13

The paired adrenal glands sit on top of the kidneys.
Each functions as two glands like the pituitary gland.
Adrenal Cortex – the outer glandular cortex that secretes a variety of steroid hormones (cortisol).
Adrenal Medulla – the inner neural medulla that secretes catecholamines (mostly epinephrine).

Question 14

thyroid gland

Answer 14

Located just below the larynx
Has 2 distinct endocrine cell types:
Follicular cells – secrete thyroid hormone
C cells – Parafollicular cells which secrete calcitonin, a calcium-regulating hormone

Question 15

thyroid gland:follicular cells and parafollicular cells (c cells), what are 3 hormones that regulat eth emovement of Ca and what 3 tissues do they regulate it in

Answer 15

Follicular cells secrete thyroid hormones which are essential for normal growth and development in children and have long-term effects on metabolism.
Parafollicular cells (C cells) secrete Calcitonin which is involved in calcium homeostasis by:
lowering blood calcium
inhibiting breakdown of calcium from bone and deposits on bone
stimulating kidneys to excrete calcium
3 hormones regulate the movement of Ca2+ between bone, kidney, and intestine: calcitonin, calcitriol, parathyroid hormone

Question 16

parathyroid glands

Answer 16

4 Parathyroid glands embedded in the back of the thyroid gland
Secrete Parathyroid Hormone (PTH)
Function: to increase plasma Ca2+ concentrations

Question 17

parathyroid glands

Answer 17

The stimulus for PTH release is a decrease in plasma Ca2+, monitored by a cell membrane Ca2+-sensing receptor (CaSR) found on parathyroid cells.
CaSR, is a G protein-coupled receptor
PTH acts on bone, kidney, and intestine to increase plasma Ca2+ concentrations
Negative feedback control shuts off PTH secretion

Question 18

relfex pathway for endocrine

Answer 18

Stimulus
Sensor
Input signal
Integration
Output (efferent) signal (hormone in blood)
Targets
Response physiological action
Negative feedback

Question 19

pancreas

Answer 19

the pancreas has tissue that acts as both exocrine and endcrine glands
endocrine glands cells located in islets of langerhans.

Question 20

pancreas

Answer 20

Most pancreatic tissue is devoted to the production and exocrine secretion of digestive enzymes and bicarbonate.
2% of the total mass is made up of endocrine cells found in the islets of langerhans which secrete antagonistic hormones that regulate blood sugar.
Glucagon, secreted by alpha cells, increase glucose levels
Insulin, secreted by beta cells, lower glucose levels

Question 21

action of insulin

Answer 21

1. Insulin bind to membrane receptor on its target cells.
2. The insulin receptor has tyrosine kinase activity, which initiates complex intracellular cascades.
3. Vesicles with GLUT 4 carrier proteins bind to the membrane.
4. Glucose diffuses through GLUT4 channels
   Occurs in adipose, muscle, and the liver

Question 22

endocrine pathways for insulin secretion

Answer 22

Insulin secretion can be triggered by signals from the nervous system or by a hormone secreted from the digestive tract after a meal is eaten.
The pancreatic endocrine cells—the integrating center for these reflexes pathways—therefore must evaluate input signals from multiple sources when “deciding” whether to secrete insulin.

Question 23

endocrine pathologies

Answer 23

“There are no good or bad hormones. A balance of hormones is important for a healthy life…Unbalance leads to disease” – W. Konig (Preface of Peptide and Proteins Hormones, New York: VCH Publishers, 1993)

There are 3 basic patterns of endocrine pathology:

1. Hormone excess
2. Hormone deficiency
3. Abnormal responsiveness of target tissue to a hormone

Question 24

endocrine pathologies: hormone excess

Answer 24

If a hormone is present in excessive amounts (Hypersecretion), the normal effects of the hormone are exaggerated.
Causes of hypersecretion include: benign tumors, cancerous tumors of the endocrine glands, exogenous iatrogenic treatment (exogenous – any substance coming from outside the body; iatrogenic – a physician caused condition due to medical treatment)

Question 25

goiter

Answer 25

excessive stimulation of the thyroid gland by TSH cuases the gland to enlarge

Question 26

acromegaly

Answer 26

excess growth hormone secretion in adults causes acromegaly, with lengthening of the jaw, coarsening of the features, and growth in hands and feet.

Question 27

endocrine pathologies: hormoen deficiency

Answer 27

Symptoms of hormone deficiency occur when too little hormone is secreted (Hyposecretion).
Hyposecretion may occur anywhere along the endocrine control pathway, in the hypothalamus, pituitary, or other endocrine glands.
Causes include: Atrophy of the gland due to some disease process (atrophy – the loss of cell mass), absence or decrease of synthesis material.

Question 28

myxedema

Answer 28

in hypothyroid individuals, mucopolysaccharide deposits beneath the skin may cause bags under the eyes

Question 29

diet and hypothroidism

Answer 29

if too little iodine to manufacture iodinated hormone

Question 30

endocrine pathologies abnormal responsiveness

Answer 30

Endocrine diseases do not always arise from problems with endocrine glands. They may also be triggered by changes in the responsiveness of target tissues to the hormones.
Even though hormone levels may be within the normal range, the target tissues are responding abnormally perhaps due to:
Down-Regulation of their receptors – Target cells may down-regulate (decrease their number of) their receptors. Example: Hyperinsulinemia
Receptor Abnormalities – Mutations can alter the protein sequence of the receptor so that it no longer binds to its specific hormone or a receptor may be completely absent. Example: Testicular feminizing syndrome
Signal Transduction Abnormalities – Genetic alterations in signal transduction pathways can lead to symptoms of hormone excess or deficiency. Example: Pseudohypoparathyroidism