Human Physiology Unit 2

Synapse

neurons transmit signals quickly over long distances by electrical means along the neuron and by chemical means

Hormones

these messengers transmit signals (more slowly than the nervous system) by altering protein synthesis or via the G protein cascade

Lipophilic (Hydrophobic)

messengers are transported in the blood mainly bound to carriers

Lipophobic (Hydrophilic)

messgers are transported in dissolved state

Lipophobic Messenger (Hydrophilic) Chemical Classes

amino acids, amines, peptides

Lipophilic Messenger (Hydrophobic) Chemical Classes

steroids, eicosanoids, thyroid hormones

Storage in Secretory Cells for Lipophobic (Hydrophilic) Messenger

secretory vesicles

Storage in Secretory Cells for Lipophilic (Hydrophobic) Messenger

none

Transportation in Blood for Lipophobic (Hydrophilic) Messenger

dissolved

Transportation in Blood for Lipophilic (Hydrophobic) Messenger

bound to carrier protein

Location of Receptor for Lipophobic (Hydrophilic) Messenger

plasma membrane

Location of Receptor for Lipophilic (Hydrophobic) Messenger

cytosol or nucleus

Signal Transduction Mechanism for Lipophobic (Hydrophilic) Messenger

open/close ion channels, activate membrane-bound enzymes, G proteins and second messenger systems

Signal Transduction Mechanism for Lipophilic (Hydrophobic) Messenger

alter transcription of mRNA

Relative Time to Onset of Response for Lipophobic (Hydrophilic) Messenger

fast

Relative Time to Onset of Response for Lipophilic (Hydrophobic) Messenger

slow

Relative Duration of Response for Lipophobic (Hydrophilic) Messenger

short

Relative Duration of Response for Lipophilic (Hydrophobic) Messenger

long

Relative Half-Life for Lipophobic (Hydrophilic) Messenger

short

Relative Half-Life for Lipophilic (Hydrophobic) Messenger

long

Hormone Secreted by Exocytosis into Blood Vessel and then Dissolved

hydrophilic messenger - shorter half-life

Hormone Secreted by Diffusion into Blood Vessel and then Bound to Carrier Proteins

hydrophobic messenger - longer half-life

Upregulation

an increase in number of receptors in/on a cell due to reduced messenger (ligand) concentrations

Downregulation

a decrease in number of receptors in/on a cell due to increased messenger (ligand) concentrations

Agonist

messenger (ligand) that stimulates a biological response by the target cell

Antagonist

messenger (ligand) that blocks an agonist from binding to its receptor on a target cell (inhibiting the agonist’s ability to stimulate an effect)

Endocrine Glands

secrete hormones into the interstitial fluid which then diffuse to bloodstream

Exocrine Glands

secrete their product into ducts that pass to the external environment

Primary Endocrine Glands

function is to secrete hormones

Secondary Endocrine Glands

secretion of hormones is secondary to another function of the organ

Hypothalamus what does it do

releasing and realize inhibitory hormones —> regulate secretion of anterior pituitary hormones

Growth Hormones (GH)

essential for growth; stimulates bone and soft tissue growth; regulates protein, lipid, and carbohydrate metabolism. even released during adulthood, just don’t get taller

Adrenocorticotropic hormone (ACTH)

stimulates glucocorticoid secretion by the adrenal cortex

Thyroid Stimulating Hormone (TSH)

stimulates secretion of thyroid hormones by the thyroid gland

Prolactin

stimulates development of breasts and breast milk secretion by the mammary glands. only released when mother is nursing or going to nurse baby

Follicle Stimulating Hormone (FSH)

Females: stimulates growth and development of ovarian follicles, estrogen secretion; males: stimulates sperm production by the tesits (female monthly cycle)

Lutenizing Hormone (LH)

Females: stimulates ovulation, transformation of ovarian follicle into corpus lute, and secretion of estrogen and progesterone; males: stimulates secretion by the tesits

Posterior Pituitary Gland - Antidiuretic Hormone (ADH, or vasopressin)

decreases urine output by the kidneys; promotes constriction of blood vessels (arterioles)

Oxytocin

females: stimulates uterine contractions and milk ejection system

Pineal Gland - Melatonin

regulates biological rhythms according to day-night cycles

Thymus - Thymosin

stimulates proliferation and function of T lymphocytes

Thyroid Gland - Thyroid hormones (triiodothyronine and tetraiodothyronine)

increase basal metabolic rate; necessary for normal development

Thyroid Gland - Calcitonin

promotes calcium deposition in bone; lowers blood calcium levels

Parathyroid Glands - Parathyroid Hormone (PTH)

promotes calcium release from bone, calcium absorption by intestine, and calcium reabsorption by kidney tubules; raises blood calcium levels; stimulates vitamin D3 synthesis

Adrenal Cortex - Mineralocorticoids (aldosterone)

stimulate sodium reabsorption and potassium secretion by kidney tubules

Adrenal Cortex - Glucocorticoids (cortisol and corticosterone)

promote catabolism of proteins and fats; raise blood glucose levels; adapt the body to stress

Adrenal Cortex - Androgens (dehydroepiondrosterone and androstenedione)

promote sex drive

Adrenal Medulla - Epinephrine

stimulates fight or flight response

Adrenal Medulla - Insulin

lowers blood glucose levels; stores energy by promoting protein, lipid, and glycogen synthesis

Adrenal Medulla - Glucagon

raises blood glucose levels; mobilizes energy by promoting glycogenolysis, gluconeogenisis

Adrenal Medulla - Somatostatin

inhibits secretion of pancreatic hormones; regulates digestion and absorption of nutrients by gastrointestinal system

Gonads - Testes - Androgens (testosterone and androstenedione)

necessary for sperm production by testis; promote sex drive and development of secondary sex characteristics (facial hair, deep voice, etc)

Gonads - Ovaries - Estrogens (estradiol) what does it do

necessary for follicular development; promotes development of secondary sex characteristics (breasts, body fat distribution, etc)

Gonads - Ovaries - Progestins (progesterone)

promotes endometrial growth to prepare uterus for pregnancy

Placenta Hormones and Function

chorionic gonadotropin, estrogens, progesterone; maintain corpus luteum, reinforces actions of hormones secreted by corpus luteum

Secondary Endocrine System - Heart Hormones and Function

atrial natriuretic peptide (ANP); inhibits sodium reabsorption by kidney tubules

Secondary Endocrine System - Kidneys Hormones and Function

renin; stimulates aldosterone secretion indirectly via the renin-angiotensin system

Gastrointestinal Tract - Stomach Hormones and Function

gastrin; stimulates acid secretion by stomach and intestinal motility

Gastrointestinal Tract - Small Intestine Hormones and Function

secretin, cholecystokinin (CCK), glucose-dependent insulin tropic peptide (GIP); regulate gastrointestinal motility and secretion, regulate exocrine secretion by liver and pancreas

Liver Hormones and Function

insulin-like growth factors (IGFs); promote bone and soft tissue growth

Skin, Liver, Kidney Hormones and Functions

1,25-dihydroxy vitamin D3; promotes absorption of calcium by intestine

Hypothalamic-Anterior Pituitary/Organ Axis

linked communication system between the brain and peripheral endocrine glands tat controls vital body functions

In the Hypothalamic-Anterior Pituitary/Organ Axis, where does Prolactin Releasing Hormone, PRH, (in hypothalamus) go to?

Ant. Pit: Prolactin

Organ: Breasts

Hypothalamic-Anterior Pituitary/Organ Axis, where does Prolactin Inhibiting Hormone, PIH/dopamine (in hypothalamus) go to?

N/A, (-)

Hypothalamic-Anterior Pituitary/Organ Axis, where does Thyrotropin Releasing Hormone, TRH, (hypothalamus) go to?

Ant. Pit: Thyroid Stimulating Hormone, TSH

Organ: Triiothyronine (T3) & Tetraiodothyronine (T4)

Hypothalamic-Anterior Pituitary/Organ Axis, where does Corticotropin Releasing Hormone, CRH (hypothalamus), go to?

Ant. Pit.: Adrenocorticotropic Hormone (ACTH)

Organ: Glucocorticoids - Cortisol (Adrenal Cortex)

Hypothalamic-Anterior Pituitary/Organ Axis, where does Growth Hormone Releasing Hormone, GHRH (hypothalamus), go to?

Ant. Pit. : Growth Hormone (GH)

Organ: Liver(insulin like growth factor) & Most other Tissues(somatomedins/”growth factors”)

Hypothalamic-Anterior Pituitary/Organ Axis, where does Growth Hormone Inhibiting Hormone, GHIH (hypothalamus), go to?

N/A, (-)

Hypothalamic-Anterior Pituitary/Organ Axis, where does Gonadotropic Releasing Hormone, GnRH (hypothalamus), go to?

Ant. Pit. : Follicle Stimulating Hormone, FSH & Luteinizing Hormone, LH

Organs: Ovaries & Testis —> estrogens, progesterone, testosterone (androgens)

Where is the thyroid gland located?

neck

What do thyroid hormones do?

increase metabolism rate, heat production, responsiveness to sympathetic nervous system activity

promote normal growth and activity

Where are thyroid hormones synthesized?

thyroid gland follicles

Follicles:

composed of a single cell layer of follicular cells in thyroid gland and the colloid secreted to the internal aspect

Thyroglobulin:

found in colloid; this is a protein that serves as the precursor for the thyroid hormones

Where is the adrenal gland located?

on top of each kidney; cortez (outer) and medulla (inner) portions

Cortex produces:

glucocorticoids and mineralocorticoids

Medulla produces:

epinephrine

Where is the Pancreas located

in abdominal cavity below stomach

What do Pancreas Alpha Cells produce

glucagon

What do Pancreas Beta Cells produce

insulin

Glucagon is released in response to:

low plasma glucose

high plasma amino acids

increased sympathetic activity

increased epinephrine release

Primary function of Glucagon

stimulates breakdown of glycogen

Insulin is released in response to what

high blood glucose

Primary function of insulin is to:

stimulate uptake of blood glucose into cells

Gamete

each parent provides one (males: spermatozoa. females: ovum)

Gamete cells are:

haploid cells

The newly formed celling following fertilization is called a:

zygote

Zygotes are:

diploid (half the genetic material of the father and half from the mother)

Following fertilization, the zygote divides into billions of different cells that initially become an embryo (first two months) and then a fetus (months 3-9). What is this process called?

Pregnancy (gestation)

The ovum contains an X chromosome; 50% of sperm have an X chromosome and 50% have a Y chromosome; this, when fertilization occurs, there is a 50-50 chance that the zygote will have either two X chromosomes or one X and one Y chromosome

Gender determination

Primary hormones for male reproductive function are:

Gonadotropin-releasing hormone, Gonadotropins, and Androgens

Gonadotropin-Releasing Hormone where is it from

from hypothalamus

What are Gonadotropins

Follicle-Stimulating Hormone & Luteinizing Hormone

Androgens

From testis —> testosterone

Selected actions of androgens in males

stimulate spermatogenesis

promote development of secondary sex characteristics ding puberty and maintenance of these characteristics in adult life

increase sex drive

stimulate growth hormone secretion, which permits bone growth during adolescence

promote development of male reproductive structures during embryonic life

Ova (eggs; oocytes) develop from:

develop from germ cells

Releasing of eggs during a woman’s life

~400, 1 every 28 day cycle for 30-35 years)

Ovaries are

female gonads that contain follicles

Follicles contain

a single developing ovum

Menstrual Cycle

28 day cycle involving hormonal changes, and structural/function changes in the female reproductive system