Endocrine system Flashcards
Endocrine system fxn
Responses usually slower and long-lasting (minutes to days)
Controls long-term processes - growth, metamorphosis, etc
Endocrine glands (6)
pituitary
thyroid
adrenal
pancreas
ovary
testicles
Two types of glands
exocrine and endocrine glands
exocrine glands
Have ducts for discharging onto a free surface - into the GI or somewhere outside the body
Endocrine glands
Small, well-vascularized, ductless glands that stay contained within the body
alpha cell
makes glucagon
beta cell
makes insulin
alpha and beta cells are where?
In the pancreas, and specifically in the islet of Langerhans
Acinar cell
make the pancreatic juice (enzymes)
What are hormones and how do they work?
Chemical messengers
Produced by an endocrine gland -> carried by blood to a target organ -> interact with target organs via receptors on/in the cells of those organs
Water-soluble hormones
Act through receptors on the cell membrane (protein hormones, amino acid derivatives)
Fat-soluble hormones
Act through nuclear or cytoplasmic receptors
(steroids such as estrogen and testosterone)
transmembrane proteins
embedded in the cell membrane ->
act as receptors for various things floating in the blood
Action via cell surface receptors
what kind?
Water-soluble hormone
1.) hormone diffuses out of capillary and binds to receptor in the cell membrane
2.) Binding triggers release of a second messenger
3.) second messenger triggers a series of reactions that alter the physiology of the cell
Action via cytoplasmic or nuclear receptors
what kind?
Fat-soluble hormones
hormone binds to receptor located in nucleus or cytoplasm
Receptor-hormone complex binds to DNA and turns on one or more genes
Activated genes direct synthesis of new proteins
Hormones of pituitary gland and hypothalamus
pituitary gland is also called
master gland - ant pit/post pit
post pit
Neurohypophysis - connected to hypothalamus via infundibulum
Ant pit
adenohypophysis - connected to hypothalamus via hypophyseal portal system
Hypothalamus secretes…
hormones
4 tropic hormones
hormones that regulate other endocrine glands
thyroid stimulating hormone
adrenocorticotropic hormone
follicle stimulating hormone
Melanophore stimulating hormone
causes pigment to disperse towards skin and causes the skin to darken
-aids in thermoregulation
-aids in camouflage
-send social signals
Skin lightening is under nervous control, not hormone control
prolactin
promotes lactation in response to the suckling stimulus of young mammals
in birds, stimulates parental behavior
in amphibians, it promotes mating behavior
helps regulate timing of metamorphosis in amphibians
Involved in water balance in anadromous fishes
Growth hormone
Stimulates growth, cell reproduction, and regeneration
Fuels childhood growth and helps maintain tissues and organs throughout life
In middle age, the pituitary gland slowly reduces its production of GH
thyroid stimulating hormone
travels to the thyroid gland and stimulates it
adrenocorticotropic hormone
Acts on the adrenal cortex
Stimulates adrenal cortex to produce hormones (aldosterone and cortisol)
Gonadotropin types
Follicle stimulating hormone
-promotes gamete production in males and females
-stimulates estrogen secretion by the ovaries
Luteinizing hormone
-stimulates production of sex hormones (estrogen and progesterone in females; testosterone in males)
-induces ovulation in females
