Endocrine System Chapter 13 Flashcards
Endocrine
Includes cells, tissues, and organs (collectively called endocrine glands) secretes hormones which act on target cells
Local hormones
Paracrine hormone
Autocrine hormone
Paracrine hormone
Released into interstitial for local action
Autocrine hormone
affect only the secreting cell (or self)
Hormone
a biochemical secreted by a cell to affect the function of other cells (or itself) by means of contact or blood transport to these target cells with specific receptors of proteins or glycoprotiens
Functions of hormones
Regulate metabolic processes
control rates of some chemical reactions
Aid in transport through membranes
Regulate water balance, electrolyte balance, BP, reproduction and growth
Types of hormones
Steroid and nonsteroidal
Steroid
Synthesized from cholesterol. Soluble in lipids, diffuse into cells to activate genes on DNA to synthesize specific proteins or can inhibit genes
Prostaglandins
Produced in a wide variety of cells; regulate neighboring cells (paracrine secretions)
Actions of hormones
Alter metabolic processes
Nonsteroid
a hormone that is the first messenger. binds to specific receptor molecule complex on the membrane. This causes its activity site to chemically alter the membrane transport mechanisms.
Control
three different systems but all employ negative feedback. Hormones have half live.
Three control systems
Hormonal
Nervous
Vascular
Hormonal
Hypothalamus->ant pituitary: releases tropic (influencing) hormones stimulating other endocrine glands to release
Nervous
nervous system-> some endocrine glands directly
Vascular
plasma levels-> some endocrine glands directly
Pituitary
At the base of the brain, attached to the hypothalamus via infundibulum. Lies in the sella turcica
Anterior chemical hormonal
the hypothalamus secretes releasing hormones which are carried to the pituitary via the hypophyseal portal veins
5 types of secretory cells in the pituitary
Growth (GH) Prolactin (PRL) Thyroid stimulating (TSH) Adrenocorticotropic (ACTH) Follicle Stimulating (FSH) Luteinizing (LH)
Growth hormone
(somatotropin) stimulates cells to enlarge and rapidly divide, enhances protein synthesis and amino acid transfer through cell membranes. Released if protein deficiency or loooooooooow glucose
Prolactin (PRL)
milk production
Thyroid stimulating (TSH)
Excess levels lead to goiter
Adrenocorticotropic (ACTH)
Acts on adrenal cortex
Follicle stimulating (FSH)
Growth and development of follicles to secrete estrogen and mature eggs/sperm production
Luteinizing (LH)
Promotes secretion of sex hormones
Posterior (pituitary)
production via neurosecretory cells,, control via hypothalamus electrically
Antidiuretic (ADH)
Decrease urine urine formation and cause vasoconstriction because there are two different receptors on target cells
Oxytocin (OT)
Smooth muscle contraction, mild antidiuretic
Thryoid
removes iodine from the blood for producing (T3 and T4) which regulate the metabolism of CHO, proteins and fats
Thyroxine (T4)
regulates BMR, 95%
Triiodothyronine (T3)
Regulates BMR, 5X stronger
Calcitonin
Lowers blood calcium levels by inhibiting osteoclasts and stimulating osteoblasts and increasing kidney excretion
Graves
Autoimmune disease
Antibodies bind to TSH receptors, gets stimulated = overactive thyroid. 24/7 will produce thyroid hormones making a goiter
Hyperthyroidism
BMR is up
Can’t sit down
Low weight
Will have a goiter
Infantile
under active infant metabolism slows down creatinism stunted growth Mental retardation Sluggish Irreversible
Parathyroid (PTH)
increase blood calcium levels by stimulating osteoclasts and inhibiting osteoblasts and decreasing kidney excretion
Adrenal
medulla: sympathetically wired
Epiephrine
(Adrenalin) Fight/Flight, increased HR, BP, breathing,
Nonepiephrine
(nonadrenalin) fight/flight
Aldosterone
water retention by conserving sodium ions
Renin-Angiotensin system
if BP drops, the kidney releases renin which decomposes angiotensinogen releasing angiotensin I. stimulates the release of aldosterone
ACE inhibitors
treats hypertension by blocking formation of angiotensin II.
Cortisol
stimulates glucose synthesis from non carbs (gluconeogenesis)
Androgens
supplement gonads some are converted into estrogens
Cushings
comes from ACTH over stimulated adrenal cortex
elevated blood glucose
increase NA retention
Pancreas
contains both exocrine gland tissue and endocrine tissue. Endocrine portion consists of 3 kinds of secreting cells that make up the pancreatic islets
2 kinds of secreting cells in the pancreas
Glucagon
Insulin
Glucagon
- ) Glycogen into glucose
- ) Converts nonCHO into glucose
- ) Catabolize fats (breaks down to get more energy)
Insulin
- ) Glucose into glycogen (decrease sugar levels)
- ) inhibits nonCHO into glucose
- ) Facilitate diffuision of glucose into cells
- ) Amino Acids into cells
- ) Increases protein synthesis
- ) Adipose synthesis and storage of fat
Hyperglacemia
blood sugars increased
Protein synthesis
blood sugars decrease
Fat synthesis
blood sugars decrease, drops
Type 1 diabetes
Juvenile, beta cells are wiped out
Type 2 diabetes
40 and older
overweight progressively loose insulin receptors
(under exercise, over eating, hereditary)
Pineal
melatonin, nerve impulses from optic nerve eventually reach pineal gland causing a decrease in production. Part of the regulation of circarian rhythms
Thymus
behind sternum. Thymosins: wbc production and differentiation
Reproductive Glands
ovaries and testes
