Anatomy and Physiology Exam 3

What is a hormone

a mediator molecule

What is the function of a hormone

they carry messages through the blood to your organs and tissues, which tell them what to do

Exocrine gland

cells produce a secretion into duct system that empties directly on surface of body or into a cavity

Endocrine glands

secretions (hormones) enter the interstitial fluid and diffuse into the bloodstream with out flowing into a duct

Lipid-soluble hormones

diffuse through lipid bilayer of plasma membrane and bind to receptors in target cells

Examples of lipid soluble hormones

steroid, and thyroid hormones

Water-soluble hormones

binds to receptor on surface of plasma membrane, leads to production of second messenger inside the cell

Examples of water-soluble hormones

amine, peptide and protein hormones

How do lipid-soluble hormones travel in the bloodstream

transport proteins

Neural Stimulus of hormone secretion

signals come from the nervous system

Humoral Stimulus of hormone secretion

comes from chemical changes in the blood (ex pH or insulin changes)

Hormonal Stimulus of hormone secrection

also called tropic hormones; uses other hormones

Control of hormone secretion

Endocrine gland releases hormone → travels via bloodstream to target organ → target organ restores homeostasis

Negative vs Positive Feedback System

Most are negative, looking to main homeostasis; Positive looks to increase something like contractions or blood clotting

Where is the Pituitary Gland located

within the brain

What Is the Pituitary Gland connected to

The hypothalamus through the infundibulum

How does the hypothalamus influence the pituitary gland

by using neurons and neurotransmitters

Anterior Lobe of the Pituitary gland

Adenohypophysis: composed of glandular tissue which is controlled by hypothalamus for the release and inhibition of hormones which are released by the hypophyseal portal system

Posterior Lobe of the Pituitary Gland

Neurohypophysis: doesn’t produce hormones, but stores hormones produced by hypothalamus

tropic hormones

Adrenocorticotropic hormone (ACTH), Thyroid stimulating hormone (TSH), Gonadotrpins: Follicle stimulating hormone (FSH) and Luteinizing hormone (LH)

Hormones that stimulate nonendocrine tissues

growth hormone (GH) and Prolactin (PRL)

Prolactin (PRL)

Is not tropic; stimulates the mammary glands to produce milk and is produced during lactation

Growth hormone

Is not tropic; stimulates an increase in cell size and the rate of cell division in target cells

Diseases caused by an imbalance in growth hormones

giantism, dwarfism, acromegaly

Thyroid stimulation hormone (TSH)

acts on the thyroid gland to stimulate the release of thyroid hormones

Adrenocorticotropic hormone (ACTH)

controls the synthesis and secretion of glucocorticoid hormones from the adrenal cortex

Follicle Stimulating hormone (FSH)

In females, promotes development of oocytes and secretion of estrogen.

In males, promotes the production of sperm.

Luteinizing hormone (LH)

In females, causes ovulation and the secretion of estrogen and progesterone.

In males, stimulates the production and secretion of testosterone.

Paraventricular nuclei

stores oxytocin

Supraoptic nuclei

stores antidiuretic hormone (ADH)

Hypothalamohypophyseal tract

group of axons that connects hypothalamus to the posterior pituitary gland

Antidiuretic hormone (ADH)

conserves body water by decreasing urine volume; raises BP by constricting arterioles

Oxytocin

stimulates contraction of smooth muscles in the uterus during childbirth

Where is the thyroid gland located

in the throat

Structure of the thyroid gland

Looks like an H, has lateral lobes connected by isthmus

How is T3 and T4 produced

In follicular cells inside the follicles. They trap iodide which is converted to iodine. This then produced throglibin. This then makes the abundant T4 (triiodothyronine) and potent T3 (thyroxine)

Function of thyroid hormones

Increase basal metabolic rate

stimulate synthesis of proteins

increase glucose and fatty acids for ATP production

increases lipolysis

What Is a goiter

A hypertrophy of cells, T4 and T3 levels are low so TRH and TSH are increased but T4 and T3 levels stay low, so abnormal cell growth occurs. To fix this you need iodide in you diet aka salt.

Negative feedback loop of T3 and T4 levels

Low levels of T4 and T3 detected→ TRH stimulates release of TSH→ this stimulates thyroid follicular cells→ T4 and T3 released back into the blood by follicular cells→ Elevated T3 inhibits the release of TRH and TSH.

Where is the Parathyroid gland located?

On the back of the thyroid gland and is 4 little dots.

Main cell of the Parathyroid

chief cells

Chief cells

produce parathyroid hormone parathormone: this regulates Ca, Mg and phosphate in blood, also increases osteoclastic activity

Homeostasis of blood calcium

High level of Ca in blood stimulates thyroid gland parafollicular cells to release more CT→ Calcitonin inhibits osteoclasts, decreasing blood Ca levels→ Low level of Ca in blood stimulates parathyroid gland chief cells to release more PTH→ Parathyroid hormone promotes release of Ca from bones into the blood and slows loss of Ca in urine, increasing blood Ca levels

Where is the adrenal gland located

superior to the kidney

Divisions of the Adrenal Gland

the cortex and medulla

The adrenal cortex (superficial to deep)

Zona glomerulosa (mineralocorticods) → secrets adlosterone ( regulates Na & K; adjusts bp & blood volume; excretion of H)

Zona fasciculata (glucocorticoids)→ secrets cortisol

Zona reticularis (androgens)→ secrets steroids

Adrenal Medulla

modified sympathetic ganglion, chromatin cells, catecholamines (epinephrine and norepinephrine)

Homeostasis of normal glucocorticoid levels

Decreasing glucocorticoid levels→ Hypothalamus senses change→increases CRH and decrease cortisol in Ant. Pituitary→ releases increased ATCH→ effects zona fasciculate in adrenal cortex to secret glucocorticoids

Where is the pancreas located

In the first part of the small intestine under the stomach

What part of the pancreas is part of the endocrine system

the islets of Langerhans which release islet cells

What part of the pancreas belongs to the exocrine system

the acini which makes up 90% of the pancreas

Islet cells

makes

Alpha cells (glucagon)

Beta cells (insulin)

Homeostasis of blood glucose

Low blood sugar→ glucagon is released into the blood

High blood sugar→ insulin is released into the blood

Where is the pineal gland located

In the epithalamus

What does the pineal gland secret

melatonin, which helps us sleep and levels peak during the night

Location of the thymus gland

above the heart

Hormones that are produced and secreted by the thymus

Thymosins

Thymopoietnis

Thymic factor

Thymic humoral factor

Function of T lymphocytes

come from the thymus gland, makes up our immune system

GI tract hormones

Secretin: secretion of pancreatic juice and bile

Cholecystokinin (CCK): contracts gallbladder which secrets pancreatic juice and bile

Kidney hormones

Renin: increase bp due to vasoconstriction; secretion of aldosterone

Erythropoietin (EPO): increase rate of red blood cell formation

Blood vs interstitial fluid

Blood is found within vessels while interstitial fluid surrounds the vessels, they should not mix

Functions of blood

Transport: O2, CO2, nutrients, waste, heat

Regulation: homeostasis, pH (buffers), body temp

Protection: clotting, immune system

Properties of blood

pH: 7.35-7.45

Temperature: 100.4 F

Volume: 55% plasma, 45% formed elements

Plasma

55% of blood

Is 90% water and 10% solutes (proteins: albumin, globulins, fibrinogens)

Formed elements

45 % of blood

They are cells or cell fragments like RBCs, WBCs, & platelets

Hemopoiesis

development of formed elements formed in red bone marrow and from hemocytoblasts (pluripotent stem cells)

Erythrocytes

red blood cells

Erythrocytes Anatomy

biconcave disks that are flexible

lack nuclei and other organelles- anaerobic

120 day life span

transport gases

contain hemoglobin (O2 carrying protein)

Hematocrit

% of total blood volume occupied by RBCs

38-46 % in women

40-54 % in Men

Hematocrit disorders

Anemia- low hematocrit

Polycythemia- high hematocrit

Erythropoiesis

RBC production stimulated by reduced O2 to kidneys → which releases erythropoietin (hormone)

The target tissue is red bone marrow

Hypoxia

cellular O2 deprivation

Causes of Hypoxia

Hemorrhage- decrease in # of RBCs

High altitudes- decrease in O2

Aerobic exercise- increase demand for O2

Homeostatic oxygen level feedback loop

Low O2→ kidney detect change→ release erythropoietin into blood→pro erythroblasts in red bone marrow makes reticulocytes which enters the blood→ more RBCs means more O2 in circulation

Hemoglobin

Heme and global in spleen

Global Protein

is recycled and is made up of 4 polypeptide chains

Heme

iron combines with transferrin; stored in lover as ferritin

Bilirubin incorporated into bile; excreted as part of feces or urine

Formation of RBCs

RBC death and phagocytosis→global sep from heme→ global broken down into amino acids to be reused→ Heme broken down to iron→ iron attached to transferrin and is stored in the liver as ferritin→ pulled out and turned back into iron and transferrin and goes to red bone marrow to go through erythropoeises→ Heme broken down to biliverdin→ turned into bilirubin→ goes to liver and then small intestine to be released as feces or urine

Important parts to erythropoiesis

Iron, global, vitamin B12 and erythropoietin

Leukocytes

white blood cells

Leukocytes anatomy

nucleated, they defend against disease and have a life span of a few days, months or years

Diapedesis

moves WBCs from circulation to interstitial fluid

Granular Leukocytes

fluid filed packet

Neutrophil, Eosinophil, Basophil

Agranular Leukocytes

Lymphocyte, monocyte

Platelets

pieces of megakaryocytic, has a life span of 5-9 days, crucial in blood clotting

How is blood type determined

genetically by the glycoproteins or glycolipids found on the surface of cells (antigens)

How are blood types named

by the antigen found on the surface of the cell

A antigen has

B antibody

B antigen has

A antibody

AB antigens have

no antibody

No antigens has

both A and B antibodies

What can type A receive

Type O and Type A

What can type B receive

Type O and Type B

What can type AB receive

Type A, B, AB and O

What can type O receive

Type O

Agglutination

clumping that occurs when someone’s antibodies contact a foreign cell

Factor that determines if our blood is positive or negative

Rh

Hemolytic Disease

a blood disorder in newborns that result from their mother being Rh negative and having Rh antigens when the newborn is Rh positive

Coverings of the heart superficial to deep

Pericardium, Fibrous, Serous, Parietal Layer, Pericardial cavity, Visceral layer

Anatomy of the heart wall

Epicardium (visceral layer), myocardium (cardiac muscle), endocardium (smooth muscle tissue that touches the blood)