A&P 2 Exam #1 Study

System composed of ductless glands that synthesize and secrete hormones.

Endocrine System

In endocrine system, hormones are released…

Directly into the blood and transported throughout the body

Cells that have specific receptors for a specific incoming hormone.

Target Cell

Target cells bind to a “blank”

Hormone

Ligands (chemical messengers) are released by what

Endocrine and Nervous System

Unlike the nervous system, the endocrine system trasnports hormones via?

Blood

Do hormones transmitted through the blood take longer or shorter amounts of time to react?

Longer

Do hormones transmitted via endocrine system through the blood last longer or shorter than NTM in nervous tissue?

Much longer

What type of tissue covers and lines endocrine glands?

Epithelial Tissue

Hormone release is regulated by which three types of stimulation?

Humoral, Hormonal, Nervous

A gland cell releases its hormone when another hormone binds to it.

Hormonal Stimulation

Gland cell releases its hormone when there is a certain change in levels of a nutrient or ion in blood.

Humoral Stimulation

Gland cell releases its hormone when a neuron stimulates it.

Nervous System stimulation

Lipid-soluble hormone, synthesized from cholesterol.

Steroids

Modified amino acid. Water soluble except for TH.

Biogenic Amine

Most hormones in this category. Water soluble chains of amino acids.

Proteins (peptides)

Type of hormone that requires a water soluble carrier protein in blood. Does not readily dissolve.

Lipid Soluble Hormone

Hormone that travels freely through the blood, most not using carrier proteins unless to prolong their half life.

Water Soluble Hormone

Is the binding between the hormone and carrier temporary or permanent?

Temporary

Hormones blood concentration depends on….

Rate of synthesization, and elimination

Hormone release and concentration in blood are

Positively Correlated

Hormone elimination can occur by what three ways

Enzymatic Degradation,Kidney Excretion, Target Cell Uptake

Time necessary to reduce a hormones concentration to half its original level.

Biological Half Life

Biological half life depends on the efficency of…

Elimination

Hormones with a shorter half life must be secreted…. to maintain normal concentrations in the body.

Frequently

Water soluble hormones typically have….

Shorter Half Life

Steroid hormones (lipid soluble) typically have a…

Longer Half Life

Why do lipid soluble hormones like steroids have a longer half life?

Protection by carrier proteins

“Blank” Hormones can diffuse across target cell membrane. Small, nonpolar, and lipophilic. Bind DIRECTLY onto nucleus. Form hormone-receptor complex.

Lipid Soluble Hormones

Hormone receptor complex binds to a “blank” of DNA, resulting in transcription of mRNA, which translated into a protein.

Hormone Response Element (HRE)

Water soluble hormones “blank” bind directly onto a nucleus of cell.

Cannot

Why can’t water soluble proteins bind to cell nucleus directly.

Cannot pass through the bilipid layer, it is too polarized.

Binding of Water Soluble Hormone to cell surface receptor activates a..

Signal Transduction Pathway

In a signal transduction pathway, hormone is the

First messenger

Hormone binding activates what protein.

G Protein

G protein Activates…

Adenlyate Cyclase

Adenlyate cyclase catalyzes formation of a secondary messenger, which…

Modifies Cellular Activity

Label the steps of signal transduction pathway in order.

Hormone Binding > G Protein Activation > Adenalyate Cyclase Activation > Secondary messenger formation

A cells response to a hormone varies with…

Number of Receptors for the hormone, Simulataneous response to other hormones

Increases number of receptors, increasing sensitivity to hormone. Occurs when blood levels of hormone are low, as well as development changes/cell cycle.

Up-Regulation

Decrease number of receptors, decreasing sensitivity to hormone. Sometimes can occur if blood hormone levels are too high.

Down-regulation

One hormone reinforces activity of another hormone. (Ex. estrogen and progesterone effects)

Synergistic Interaction

One hormone requires activity of another hormone. (Ex. oxytocin milk ejection effect requires prolactin milk generation)

Permissive interaction

One hormone opposes activity of another hormone (Ex.. glucagon increasing blood glucose while insulin lowers it)

Antagonistic Interactions

Gland in control of pituitary, as well as in control of many other endocrine glands.

Hypothalamus

Pea sized gland lied inferior to hypothalamus. Partitioned into an anterior and posterior section.

Pituitary

What is the structure connecting the hypothalamus and pituitary?

Infundibulum

Hypothalamus sends its hormones to the POSTERIOR pituitary via a?

Hypothalmo-hypophyseal TRACT

The hormones in the hypophyseal portal TRACT travel via….

Neurons vesicles

System of blood vessels connecting the hypothalamus to the ANTERIOR pituitary.

Hypothalmo Hypophyseal Portal System

Hormones in the hypothalmo hypophyseal portal system travel via…

Blood in Veins

Capillary Network associated with hypothalamus.

Primary Plexus

Drain primary plexus and transport to secondary plexus.

Hypophyseal Portal Veins

Capillary Network associated with anterior pituitary

Secondary Plexus

Site of storage and release of hormones from hypothalamus. No hormones made here.

Posterior Pituitary

Released by Posterior Pituitary (made in supraoptic nucleus of hypothalamus), functions to decrease urine production, stimulate thirst, and constrict blood vessels.

ADH (vasopressin)

Released by Posterior Pituitary (made in paraventricular hypothalamus), functions include uterine contraction, milk ejection, emotional bonding.

Oxytocin

Hormones (like ADH and Oxytocin) are sent down the tract via axonal transport, are packed into…

Secretory Vesicles

The hypothalamus stimulates which gland to release its hormones, via regulatory hormones.

Anterior Pituitary Gland

What two types of hormones does the Hypothalamus send to anterior P.?

Releasing Hormones (RHs), Inhibiting Hormones (IHs)

Hormones sent from the hypothalamus to secrete another hormone.

RH

Decrease secretion of anterior pituitary hormone.

IH

(Hormone of A.P) Release triggered by TRH from hypothalamus, causes release of thyroid hormone in thyroid gland.

TSH

(A.P Hormone) Release triggered by PRH. (Prolactin releasing hormone) inhibited by PIH from hypothalamus. Causes milk production, mammary gland growth.

Prolactin

(A.P.) Hormone. Release triggered by CRH from hypothalamus. causes release of corticosteroids by adrenal cortex.

ACTH (Adrencorticoptropic hormone)

(AP Hormone) release triggered by GnRH from hypothalamus. In females, regulates ovarian development as well as estrogen and progesterone release. In Males, sperm development and secretement of testosterone.

FSH/LH (Follice Stimulating/Lutenizing Hormone)

(AP Hormone) Causes liver hormone to secrete insulin like growth factors 1 and 2. (IGF-1 and IGF-2)

GH (Growth Hormone/Somatotropin)

Hormones that stimulate other endocrine glands to release their hormones.

Tropic Hormones

Place the steps of GH Release in Correct Order.

1. GHRH stimulates anterior pituitary to release growth hormone (GH)

2. Hypothalamus releases GHRH into hypothalmo-hypophyseal portal system.

3. GH stimulates liver to release insulin-like growth factors (IGFs)

4. GH and IGFs regulated by negative feedback

5. GH and IGFs stimulate target cells; stimulate growth and release of

   nutrients into blood

2,1,3,5,4

Stimuli regulating release of GHRH regarding age, highest around what ages.

Children/Adolescents

GHRH decreases or increases secretion with age?

Decreases

Peak release of GHRH and GH occurs when during the day.

Night time (sleep)

An increase in what can stimulate release of GHRH and GH release.

Nutrient Intake

IGF stimulates increased…

Protein Synthesis, Cell Division, Cell Differentiation

Do IGFs or GH have a longer half life, even though their function is similar.

IGFs

GH/IGFs stimulate the release of…

Nutrients from Storage

GH/IGFs increases/stimulates

Glycogenolysis (breakdown of glycogen into glucose)

Gluconeogenesis (conversion of nutrients to glucose) stimulated

Lipolysis (breakdown of triglycerides) stimulated

GH/IGFs decreases/inhibits

Glycogenesis (synthesis of glycogen)

Lipogenesis (formation of triglycerides)

GH is highly….

Metabolically Active

Gland connected via left and right lobes, connected at midline by the “isthmus”.

Thyroid

Cuboidal epithelial cells that surround the central lumen of the thyroid gland.

Follicular Cells

Follilcular Cells produce and release

Thyroid hormones (T3 and T4)

Cells between follicles, that make calicitonin.

Parafollicular cells.

Function of calcitonin.

Decrease blood calcium levels

T3 and T4, after being released by thyroid not only increase you metabolic rate, but also

Increase the release of nutrients in the blood.

TSH by the AP relies on stimulation of what hormone by the hypothalamus?

TRH (Thyrotropin releasing Hormone)

T3 and T4 make your body more calorigenic, meaning….

Generates heat, raises your internal body temp (increased metabolic rate)

T3 and T4 foster energy production, otherwise known as help make what?

ATP

T3 and T4 also increase your respiration rate, and as a result increase..

Heart Rate and Force of contraction

T3 and T4 would make your cells store more fat/glucose (lipogenesis/glycogenesis) or make more glucose and break down more glycogen (glycogenolysis and gluconeogenesis)?

Make more/break down more

Which type of cells in particular are stimulated by T3 and T4 to increase blood glucose?

Hepatocytes

Excessive production of T3 or T4.

Hyperthyroidism

Hypothyroidism would describe….

Decreases metabolic rate, weight gain, cold intolerance.

Common disease with Hyperthyroidism.

Graves Disease

Decreased production of TH

Hypothyroidism

Hypothyroidism would describe….

Low metabolic rate, lethargy, cold intolerance, weight gain

Hypothyroidism can be caused by decreased intake of this….

Iodine

This hormone is synthesized and released from parafollicular cells of thyroid. Stimulated by high blood calcium levels from exercise.

Calcitonin

Calcitonin Functions to….

Decrease blood calcium levels via inhibition of osteoclast activity, increase excretion of calcium in urine.