tech prep

Tropic cells

produce tropic hormones that stimulate endocrine glands

Tropic cells are located in

the anterior part of the pituitary

autocrine

targets itself

paracrine

targets neighboring cell

endocrine

entire body/bloodstream

Endocrine glands secrete

hormones

hormones diffuse from the

interstitial fluid -\> blood stream -\> target cells

exocrine glands

tubes/ducts \> body surface

major endocrine glands

thyroid, hypothalamus, pituitary, adrenal, thymus

thyroid (location)

neck

hypothalamus (location)

above the brainstem; below the thalamus and above the pituitary

pituitary (location)

at the base of the brain, attached to the hypothalamus

adrenal (location)

superior end of the kidneys

thymus (location)

upper chest, behind the sternum

Pathway for steroid

Steroid binds to a receptor in the nucleus or cytoplasm -\> goes inside the nucleus -\> binds to gene -\> creates new protein / activating genes

Pathway for protein

Receptor is outside the cell (cell membrane) -\> G-protein is stimulated -\> release of adenosine cyclase is stimulated -\> converts atp into cAMP -\> cAMP is 2nd messenger -\> turns on inactive protein kinases

Anterior pituitary makes

GH, PRL, TSH, ACTH, LH, FSH

GH function

promote the growth of all body tissues and stimulates metabolism

PRL function

stimulates milk production

TSH function

stimulates thyroid gland

LH function

stimulates ovaries and testes

FSH function

stimulates production of ova and sperm

posterior pituitary stores

ADH and Oxytocin

Function of oxytocin

stimulates the contraction of the uterus

Function of ADH

promotes retention of water by kidneys

erythropoietin stimuletes

red cell production in bone marrow

eerythropoietin is synthesized in the

kidney

when does the kidney synthesize erythropoietin

when blood oxygen levels are low

insulin and glucagon are made in

pancreas in cells contained within pancreatic islet structures

Insulin is released when

blood glucose is high (after a meal)

how does insulin work

allows cells to import glucose from the blood, and regulates cell metabolism to utilize the glucose in biosynthetic reactions, to metabolize for energy (ATP), or to store as glycogen

Glucagon is released when

blood glucose levels are low

Glucagon regulates

cell metabolism to break down glycogen into glucose units

in the liver glucose is released to

help raise blood glucose levels

in other tissues glucose is

metabolized to make ATP

Type I diabetes (aka juvenile diabetes) occurs when the

pancreas cannot make insulin due to the destruction of the insulin-making beta cells.

Type II diabetes occurs when

peripheral tissues become resistant to insulin

Type II diabetes is related to

genetics, obesity and lifestyle factors.

stomach lining secretes the

gastrin

gastrin stimulates

HCl and pepsin production

thyroid gland responds to TSH by making

thyroid hormone (T3 and T4)

What is thyroid hormone made of?

iodine and tryodiothryon

low levels of T3 and T4 are often caused by

iodine deficiency

iodine deficiency can cause the formation of a

goiter

increased thyroid tissue growth is stimulated by

increased TSH

TSH is released in response to

low blood levels of T3 and T4

without sufficient iodine to make enough T3 and T4 the TSH signal results in

enhanced thyroid tissue growth

parathyroid glands

4 tiny glands on the back of the thyroid gland

parathyroid glands secrete

parathyroid hormone

parathyroid hormone is released in response to levels of

free calcium in the blood + helps regulate serum calcium levels

thyroid gland also produces

calcitonin

calcitonin decreases

blood calcium levels

high levels of t3 and t4

fast metabolism, weight loss, warmer body temperature. swelling of tissues around the eyes (bulging eyes)

adrenal glands release

cortisol and aldosterone

cortisol and aldosterone play important roles in

metabolic regulation and in the regulation of water and sodium retention (and thus blood pressure)

blood is composed of

plasma (~55%) and formed elements (cells and platelets, ~45%)

Plasma is mostly

water

Plasma also contains

electrolytes (such as sodium, potassium, calcium), proteins (primarily albumin, immunoglobulins, fibrinogen), metabolic waste (mainly ammonia, urea and creatinine), nutrients (such as glucose), vitamins, hormones, and gases (such as O2 and CO2)

Formed elements include

red blood cells (95%), platelets (4.8%), and white blood cells of all types (0.1%).

buffy coat

white fuzzy layer of white blood cells shown when blood is separated

Know that platelets are fragments of

cell cytoplasm (megakaryocyte cytoplasm)

Platelets are important in

blood clot formation.

Platelets are part of

blood clots (a blood clot is a thrombus)

platelets release

serotonin, vasoconstricting hormone, as the platelet plug forms

function of serotonin

constricts blood vessels around areas of damage which helps limit blood loss

the liver makes

serum albumin and clotting proteins

most abundant protein in the plasma

albumin

main function of albumin

water balance in the blood; maintain osmotic pressure

What happens if there isn't enough albumin

water goes into tissues -\> swelling and edema

hematopoiesis

hematopoietic stem cells differentiate into the various mature blood cell types

hematopoietic stem cells differentiate into either

myeloid or lymphoid lineages

differentiation of lymphoid precursors results in

B and T lymphocytes

differentiation of myeloid precursors results in

monocytes/macrophages, neutrophils, eosinophils, basophils (and mast cells), platelets (from megakaryocytes), and erythrocyte

hematopoiesis occurs in the

bone marrow

normal white cell count range in a healthy adult is

5,000 - 10,000 cells/ml

normal red blood cells (RBCs) are

biconcave cells that lack nuclei when mature

red cell production is regulated by

erythropoietin (EPO)

sickle cell is caused by

defective hemoglobin due to genetic mutation (1 amino acid is changed)

sickle cell causes RBC to

start to break easily, hemolysis; destruction of RBCs

iron is needed for hemoglobin to bind

oxygen

hematocrit

percentage of formed elements in the blood

red cell turnover produces

biliverdin and bilirubin (metabolic breakdown products of the heme group)

Biliverdin and bilurubin are excreted in the

feces or used to make bile salts by the liver

bile salts are stored in the

gallbladder

bile salts assist in

solubilizing dietary fats for absorption

Excess levels of bilirubin causes

jaundice, characterized by a yellow color in the eyes and skin

What is leukopenia,

low WBC count

Leukopenia is caused by

autoimmune disease or immunosuppressants

eukocytosis

high WBC count, caused when illness

Leukemia

cancer of bone marrow -\> produces a large amount of immature WBC that occupies space in the blood

clotting cascade can be activated by either an

extrinsic mechanism or an intrinsic mechanism

extrinsic mechanism becomes activate in response to

tissue damage)

intrinsic mechanism becomes activated in response to

contact with a substance other than the smooth endothelial lining of blood vessels

ctivation of Hagemann factor is the

first step to initiate the intrinsic clotting cascade

the final product of both the intrinsic and extrinsic clotting cascades is a

fibrin clot (the pathways join at Factor X)

Intrinsic

Collagen makes platelets sticky. Serotonin constricts blood vessel → less blood loss

Extrinsic

thromboplastin + Ca+ + Clotting Factors → Clotting Cascade

ABO blood group

group based on the presence (or absence) of two major antigens on the RBC membranes

A person with only antigen A has

type A blood

A person with both antigen A and B has

type AB Blood