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4th bio test 3rd
3rd set
48
Biology
Undergraduate 1
11/22/2008

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Term

plant versus animal hormones

 

Definition

-p.h. produced by any actively growing part of plant / a.h. produced by specialized endocrine glands and neurosecretory cells

-a.h travel through blood and can reach distant parts of plant

-p.h. usually have the same effect on all the cells they reach (except auxins) / a.h. bind to very specific target tissues and only have an effect there

Term
all hormone secreting tissues included in the
Definition
endocrine system
Term

endocrine system compared to nervous system

Definition

endocrine system responds to stimuli on a more long term basis

 

can take minutes, hours, or days to act because hormones may take a long time to be synthesized and travel to target cells

Term
endocrine glands -
Definition
main source of production and secretion of hormones
Term
neurosecretory cell:
Definition
specialized nerve-ending that (in addition to conducting nerve signals) makes and secretes hormones
Term
necessary steps in hormone action
Definition

1. bind to a receptor

2. activate, inactivate, or trigger some activity in target cell

3. signal amplification: one hormone molecule has a big effect

Term
categories of hormones
Definition

steroids

-sex (testosterone, androgen)

-corticosteroids (cortisol)

peptides

-chains of less than 100 amino acids (insulin)

glycoproteins

-longer polypeptide chains (FSH/LH)

amines

-secreted by thyroid, modified AA, (epinephrine)

Term
amino acids
Definition
building block of proteins
Term

lipophilic

Definition
can diffuse through the plasma layer of cells
Term
Actions of Steroids and other lipophilic hormones
Definition

after passing through phospholipid bilayer (cell membrane), binds to specific receptor protein

-receptor protein and hormone enter nucleus together

-now that receptor protein has been activated by hormone, it causes DNA to synthesize new proteins (different from itself)

 

Term
hydrophilic hormones
Definition

can't diffuse through cel membrane so they do one of two things.

1. bind to a receptor and be carried through the membrane

2. use a second messenger system

Term

2nd messenger system

Definition

one way a hydrophilic hormone affects cell

-can't get through plasma membrane so it binds to a receptor embedded in membrane

-this sends a signal to 2nd messenger (in cell) which has an effect in the cell

-typically activate or inactivate enzyme

Term

endocrine gland

Definition
secrete hormones directly into capillaries, no ducts or tubes
Term
exocrine glands
Definition

secrete stuff (enzymes) through ducts

 

i.e. sweat glands and digestive enzymes

Term
hormones involved in digestion
Definition
Gastrin, secretin, cck, GIP
Term
brain's role in digestion
Definition
sight, smell, taste, thought of food causes the release of gastrin
Term
gastrin
Definition

first hormone released in digestion

upon seeing, smelling, tasting, thinking about food, gastrin cause stomach to start producing pepsin and HCL

-upon eating more gastrin released and more pepsin and HCL released (positive feedback loop)

Term
secretin
Definition

digestive hormone

-if acid products of digestion (HCL) enters duodenum, secretin is released from duodenum which stimulates pancreas to secrete digestive enzymes into duodenum

Term
cholecystokinin (CCK)
Definition

3rd hormone released in digestion

-fats in partially digested materials in duodenum stimulate cck release

-cck stimulates gall bladder to release bile

Term
GIP
Definition

last hormone released in digestion

-stops digestive cycle

-inhibits secretion of previous three hormones and shuts off digestive process when no more partially digested material present

Term
diabetes and the pancreas
Definition
scattered among digestive enzyme secreting cells in pancreas are many patches of endocrine cells (islets of Langerhans)
Term
Islets of Langerhans
Definition

endocrine cells in pancreas

-two types:

alpha - secrete glucagon

beta - secrete insulin

Term
role of insulin
Definition

makes excess glucose in blood get stored in muscles (glycogen) and fat tissue (fat) 

-essentially lowers blood sugar

Term

normal digestive processes

Definition

-after meal, hepatic portal vein brings glucose, AA, etc. to liver

-liver removes surplus and stores glucose as glycogen

-between meals, liver releases gylocgen into blood as glucose

-muscle stores gluscoes as glycogen and adipose tissue stores it as fat

Term
actions of insulin
Definition

stimulates glucose uptake by muscles and adipose tissue

-inhibits glycogen from breaking down (into glucose)

-changes to glucose to glycogen in liver and muscles

-promotes synthesis of fats from glucose

Term
glucagon
Definition

-hormone that counteracts insulin

-makes glycogen get released into blood as glucose

-produced in alpha islets in pancreas

Term
hypoglycemia
Definition

results from too much insulin

-also called insulin shock

-too little sugar

-cells lack glucose, can't do cell. resp.

-results in cell death and first cells to die are nerve cells

-can result from too much insulin injection (diabetic) or pancreatic tumor

Term
hyperglycemia
Definition

to much blood sugar

-not enough insulin

-causes weakness, dehydration

Term
type I diabetes
Definition

juvenile onset

-islet cells fail to secrete insulin

Term
type II diabetes
Definition

adult onset

-insulin production normal but either removed by liver or fails to stimulate target cells

Term
posterior pituitary
Definition

extension of the hypothalamus (brain) and composed of nervous tissue

-stores and secretes hormones made in the hypothalamus

Term
anterior pituitary
Definition

non-nervous tissue

glandular tissue

synthesizes its own hormones, which may control other endocrine glands

Term
TSH
Definition

thyroid stimulating hormone

released by anterior pit.

tropic

Term
tropic hormone
Definition
hormones that stimulate a gland to secrete something
Term
ACTH
Definition

adrenocorticotropic hormone

-stimulates the adrenal cortex (in adrenal gland on top of kidney)

-released by ant pit.

tropic

Term
GH
Definition

growth hormone

-stimulates development and enlargement of all body parts

-triggered by GHRH from hypothalamus

-not tropic

-too much GH and cause giantism, too little can cause dwarfism

-released by anterior pit.

Term

gonadotropic hormones

aka gonadotropins

Definition
FSH and LH
Term
FSH
Definition

follicle stimulating hormone

tropic

stimulates follicle to develop into egg

-released from the anterior pit.

Term
LH
Definition

lutenizing hormone

-tropic

-released by anterior pit

-triggers ovulation in female

-stimulates production of testosterone in males

Term

PRL

Definition

prolactin

-stimulates mammary glands in mammals to produce milk

-regulates larval development in amphibians

comes from anterior pit.

Term
MSH
Definition

melanocyte-stimulating hormone

-stimulates melanocyte in amphibians

-released from ant. pit.

Term
oxytocin
Definition

hormone released by the POSTERIOR pituitary

-stimulates muscles of uterus to contract during childbirth

-also helps mammary glands produce milk

Term
ADH
Definition

antidiuretic hormone

aka vassopressin

-released by the POSTERIOR PITUITARY

makes collecting duct more permeable to water ultimnately resulting in more concentrated urine (more H20 uptake by peritubular capillaries)

Term
hypothalamus control over posterior pituitary
Definition
neurosecretory cells extend from the hypothalamus into the posterior pituitary and synthesize two hormones (oxytocin and ADH) which are then released into the blood
Term
hypothalamus also has some control of anterior pituitary...such as...
Definition

secretes releasing hormones: make the ant pit. secrete hormones

 and secretes inhibiting hormones: make the ant. pit. stop secreting hormones

-these hormones are secreted by neurosecretory cells at the base of the hypothalamus into small vessels leading to the Ant. pit.

Term
name the tropic hormones
Definition

TSH, ACTH, gonadotropins

 

-negative feedback mechanisms control these hormones

 

-hormones secreted by the secondary glands result in negative feedback on tropic hormones

Term
GHRH
Definition

growth hormone releasing hormone

triggers ant. pit. to release GH

 

if it ends in RH (releasing hormone), it's from the hypothalamus

Term

endorphins

Definition

type of hormone

body's natural painkillers

-released by ant. pit.

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