A&P Test 1

what are lipid soluble hormones

proteins and peptides

what can lipid soluble hormones do

target things outside of the nucleus

water soluble hormones example

glucagon, prolactin

what is the endocrine system composed of

endocrine glands that secrete chemical messengers (hormones) into circulatory system to target tissues (effectors)

what does the endocrine systyem do

workls closely with the nervous system to acieve and maintain homeostasis

where do hor mones act

do not act locally, they come from endocrine glands and are secreted into blood stream

growth and development

stimulate bone cells to secrete new matrix, neurons to form and strengthen synapses, enlargement of muscle fibers, and more

metabolism

stimulate cells to take up or release glucose, produce enzymes, modifyh heart rate, blood pressure, and respiration

blood composition

regulate kidney actions to conserve or secrete ions and water, regulate plasma pH, blood cell numbers and types, and plasma proteins

reproduction

key regulators of reproduction in the production of gametes and preparation of the female body to nourish offspring

both the nervous and endocrine syhstem have

shared brain structures, specifically the hypothalmus

what do the endocrine and nervous system both use

same chemical messenger as neurotransmitter and hormone such as epinepherine

what do endocrine and nervous system bolth do

cooperate to regulate body prolcesses

how can neurotransmitters and hormones affect their targets

G protein-coupled receptors

nervous and endocrine mode of transport

differernt, axons release neurotransmiktters directl.y onto target cells while horm ones are released into the blood to travel to terget tissues

nervous and endocrine system speed of response

nervous is instant while endocrine takes minutes or days

endocrine and nervous system modualition of signal intesnity

amplitude for endocrine vs frequency for nervous

amplitude modulated system

concentration of hormone determines strength of signal and magnitude of response

lower concentration of hormone

weak signal and produces a small response

greater concentration of hormone

stronger signal and results in greater response

frequency modulated system

strength of signal depends on frequency of action potentials

low frequency of action potentials

weak stimulus

higher frequency of action potentials

stronger stimulus

autocrine

chemical messenger secreted by cells in a local area, influences activity of the same cell from which it was secreted

autocrine example

Eicosanoids

Paracrine

chemical messenger produced by wide variety of tissues and secreted into extracellular fluid, has localized effect on nearby tissues

paracrine example

somatostatin, histamine, eicosanoids

neurotransmitter

produced by neurons, secreted into a synaptic cleft by presynaptic nerve terminals, travels short distances, influences postsynaptic cells

neurotransmitter example

acetylcholine, epinepherine

endocrine

chemical messenger secreted into the blood by specialized cells, travels some distance to target tissues, results in coordinated regulation of cell function, called hormones

endocrine examples

thyroid and growth hormone, epinepherine

what do hormones bind to

receptor proteins

specificity

shape and chemical nature of each receptor site allow only certain hormones to bind

when do some hormones release

when blood levels of certain chemicals change

when blood calcium levels are low

parathyroid hormone is released

neural stimuli

after an action potential a neuron releases a neurotransmitter into a synapse witha hormone producing cell that then secretes its hormones

neural stimuli example

release of epinepherine and norepinepherine from the adrenal medulla after sympathetic stimulation

hormonal stimuli

certain hormones secreted in response to another hormone

most hormones secreted are

tropic hormones from anterior pituitary gland to hypothalamus that act as releasing or inhibiting hormones

chronic pattern of hormone secretion

maintenance of relatively constant concentration of hormone

example of chronic hormone

thyroid

acute patterns of hormone secretion

concentration changes suddenly and irregularly

example of acute hormone

epinepherine in response to stress

episodic hormone secretion

secreted in predictable pattern

example of episodic hormone secretion

female reproductive hormones

lipid soluble hormones are

nonpolar and can pass through plasma membrane

lipid soluble hormones examples

steroids, amino acid derivatives, thyroid hormone, fatty acid derivatives

steroids

testosterone and aldosterone

amino acid derivative

thyroid hormone

fatty acid derivatives

prostaglandins

water sol.uble hormones are

polar

water soluble hormones example

proteins, peptides, amino acid deri vatives

proteins

thyroid stimulating horm one and growth hormone

peptides

insulin, thyrotropin releasing hormone

amino acid derivatives

epinepherine

hyrolytic enzymes in blood would

inactive hormon es

binding proteins can

deliver hormones to target tissues

bound hormones

can act as reservoir

reversible

releases free hormones and must be free to interact with target tissue

free hormones

immediately activate target cells blood levels fluctuate

bound hormones

circulate in blood longer and provide chronic, stable supply of hormone

Regulation of hormone levels in the blood negative feedback step 1

anterior pituitary gland secretes a tropic hormone into blood to reach target endocrine cell

Regulation of hormone levels in the blood negative feedback step 2

hormone from target endocrine cell travels to its target

Regulation of hormone levels in the blood negative feedback step 3

hormone from target endocrine cell has negative feedback on anterior pituitary and hypothalamus, decrease secretion of tropic hormone

Regulation of hormone levels in the blood positiv e feedback step 1

anterior pituitary gland secretes a tropic hormone into blood to reach target endocrine cell

Regulation of hormone levels in the blood positiv e feedback step 2

hormone from target endocrine cell travels to its target

Regulation of hormone levels in the blood positiv e feedback step 3

hormone from target endocrine cell has positive feedback effect on anterior pituitary, incrfeases secretioln of the trop;ic hormone

larger more complex hormones are

more stable

smaller sim pler hormones are

less stable

half life

amount of time it takes for half of a circulating hormone to be removed from circulatioln and excreted

all hormones are

destroyed either in circulation or by enzymes

lipid soluble hormones elimination

quickly diffuse out of capillaries, degraded by enzymes of liver or lungs, filtered out by kidneys, binding proteins prevent this

proteases

water soluble hormones broken down by enzymes in bloodstream

water soluble hormone receptors mechanisms of action

membrane-bound receptors, receptors alter either g protein activity or intracellular enzyme activity, ion channels are opened or closed and existing enzymes are activated or just existing enzymes are activated

lipid soluble hormone receptors and mechanisms of action

nuclear receptors, receptors activate genes, synthesize new proteins or enzymes

specificity

hormone binds at a specific binding site to elicit tarbget cell response

3 factors determining strength of hormone effect on target

concentration of hormone, number of receptors on target, affinity between hormolne and receptor

agonist

drug with similar structure of a specific hormone, binds to a hormone receptor and activates it

antagonist

drug that can bind to a horm one receptor and inhibits its action

receptor down receptors is also called

desensitization

rate of receptor synthesis decreases

after cells are exposed to a hormone

what can increase rate of receptor degradation

combination of hormones and receptors

receptor degradation

taken into the cell by phagocytosis and destroyed

up regulation

stimulus causes increase in receptor stimulus, increases hormone sensitivity

example of up regulation

FSH stimulation of ovary causes an increase of LH receptors, sin ce ovarian cells are more sensitive to LH this causes ovulation

lipid soluble mechanism of action

increases protein synthesis and inmcreasees the production of secon messengers

water soluble mechanims of action

activate g proteins and stiumlate synthesis of cAMP

types of membrane bound receptors

ligand-gated ion channels, g protein-coupled receptors, enzymatic receptors

GTP binding proteins allows for

transduction of extracellular signal into intracellular signal using second messengers

second messenger system

membrane receptor couples to g proteinm produces second messengers when activated

cyclic guanine monophosphate cell type

kidney cells

cyclic adenosine monophosphate cell, type

liver cells

calcium ions cell type

smooth muscle cells

Inositol triphosphate cell type

smooth muscle cells

diacylglycerol cell type

smooth muscle cells

cyclic guanine monophosphate response

increased Na+ and water excretion by the kidneys

cyclic adenosine monophosphate response

increased breakdown of glycogen and release of glucose into the circulatory system

calcium ions response

contraction of smooth muscle cells

Inositol triphosphate response

contraction of certain smooth muscle cells in response to epinepherine

diacylglycerol response

contraction of certain smooth mujscle cells in response to epinepherine