Chapter 16 - Endocrine Flashcards
First messenger
The hormone
Second messenger
Intracellular intermediary that activates after a hormone binds to a receptor in the plasma membrane.
Cyclic AMP (cAMP)
An important second messenger, a derivative of ATP
Hypothalamus
Exerts direct or indirect control over the activities of many endocrine organs
3 hypothalamic control mechanisms
1) ADH and OXT via posterior pituitary
2) regulatory hormones via anterior pituitary
3) autonomic centers via preganglionic fibers to the adrenal medulla
Fenestrated capillaries
Unusually permeable endothelial cells found at the median eminence of the infundibulum that allow relatively large molecules to enter or leave the blood stream.
Hypophyseal portal system
Capillary networks and interconnecting vessels. Efficient means of chemical communication. Strictly one way communication.
Tropic hormones
Hormones of the anterior pituitary, called that because tropic = a turning
Diabetes mellitus
Characterized by glucose concentrations that are high enough to overwhelm the reabsorption capabilities of the kidneys.
Type 1 diabetes
Inadequate insulin production by the pancreatic beta cells. Develops in children and young adults.
Type 2 diabetes
Most common form. Patients develop insulin resistance.
Diabetic retinopathy
Proliferation of capillaries and hemorrhaging at the retina, may cause blindness.
Diabetic nephropathy
Degenerative changes in the kidney, can lead to kidney failure.
Diabetic neuropathy
Abnormal blood flow to neural tissues causing a variety of problems with peripheral nerves.
Stress
Any condition - whether physical or emotional - that threatens homeostasis.
Stress response or general adaptation syndrome.
3 phases
1) alarm phase
2) resistance phase
3) exhaustion phase
Alarm phase of GAS
Immediate response to stress directed by the sympathetic nervous system.
Energy reserves are mobilized in form of glucose
Body prepares to deal with stress
Resistance phase of GAS
If stress lasts longer than a few hours. Glucocorticoids are dominant hormone of this phase. Neural tissue is hungry for glucose, so the hormones of this phase shift tissue metabolism to lipids and amino acids.
Exhaustion phase of GAS
Body’s lipid stores are sufficient to maintain the resistance phase for weeks or months, but not indefinitely. Homeostatic regulation breaks down during exhaustion.
Conservation of NA+ at expense of K+
Acromegaly
Results from overproduction of growth hormone after epiphyseal played have fused.
Goiter
Enlarged thyroid gland
Infantile hypothyroidism
Congenital disorder due to thyroid hormone deficiency. Mental disability, puffy face, thick tongue.
Addison’s disease
Hypo secretion of corticosteroids. Pigment changes result from stimulation of melanocytes
Cushings disease
Hypersecretion of glucocorticoids. Lipid reserves are mobilized, and adipose tissue accumulates in cheeks and at the base of the neck.
Receptor
Protein molecule to which a particular molecule binds strongly.
