AP Exam 1

what are the differences between autocrine and paracrine signaling and how does it differ from endocrine signaling?

autocrine- chemicals that exert effects on same cells that secrete them

paracrine- locally acting chemicals that affect neighboring cells

what are the 2 types of hormones based on its composition? (amino-acid based, steroid based)?

steroids

• synthesized from cholesterol

• lipid soluble, can cross plasma membrane

• includes gonadal and adrenocortical hormone

amino acid base- most hormones are this, amino acid derivatives, peptides, and proteins

• water soluble (except thyroxine), cannot cross plasma membrane

what are eicosanoids? give examples of it

classified as paracrines and autocrines given their highly localized effects

ex.

• prostaglandins: reg. inflammation, pain, fever, vasodilation, and uterine contractions

• thromboxane: promote platelet aggregation and vasoconstriction: key in blood clotting

what are the mechanisms by which hormones take effect in the target cell? (water soluble hormones: 2nd messenger system signaling and steroid hormones/thyroid hormones: direct gene activation?

water soluble hormones- (insulin, epinephrine, FSH)- cannot pass through the cell membrane because they’re polar, they require a second messenger systems- cyclic AMP and PIP2- calcium signaling mechanism

steroid hormones/thyroid hormones: direct gene activation?

receptor hormone complex enters nucleus; binds to specific region of DNA

• binding “turns on” gene to initiate DNA transcription to produce mRNA

• mRNA is then translated into a specific protein

  -proteins synthesized have various functions, including:

  -metabolic activities, structural purposes, or extracellular functions (after being exported from cell)

what is the hypothalamic tract? (direct gene activation)

axons connecting hypothalamus to posterior pituitary form the tract

what is the hypothalamic-hypophyseal portal system? (direct gene activation)

releasing and inhibiting hormones from the hypothalamus travel through portal to anterior pituitary gland to regulate secretion of 6 hormones:

GH, TSH, ACTH, FSH, LH, PRL

permissiveness

one hormone cannot exert its effects without another hormone being present

synergism

more than one hormone produces same effects at target cell and combined effects are amplified

e.g. glucagon causes liver to release glucose

antagonism

one or more hormones oppose action of another hormone

e.g. insulin and glucagon

what kind of interaction do calcitonin and insulin have in target cells?

synergism

parathyroid hormone

most important hormone in Ca2+ homeostasis

• falling blood levels Ca2+ stimulate

• rising blood inhibits

• target organs: bones, kidneys, and small intestine

component of the blood

plasma- 55% of whole blood

buffy coat- <1% of WBCs and platelets

erythrocytes- 45% of whole blood (hematocrit)

what are the formed elements?

blood cells and platelets (thrombocytes), WBCs (leukocytes)

how are erythrocytes develop/form?

1. hypoxia (inadequate O2 levels)

2. kidney releases erythropoietin

3. erythropoietin stimulates red bone marrow

4. enhanced erythropoiesis increases RBC count

5. O2 carrying ability of blood cells

what are the function of erythrocytes?

dedicated to respiratory gas transport

what are the functions of leukocytes?

defense against disease

• make up <1% of total blood volume

• cross capillary walls to leave the blood stream, called diapedesis

different kinds of leukocytes?

granulocytes and agranulocytes

what are granulocytes?

with cytoplasmic granules (neutrophils, eosinophils, basophils)

what are agranulocytes?

lack cytoplasmic granules (lymphocytes, monocytes)

what is normal blood pH range?

7.35.7.45

what is albumin?

makes up 60% of plasma proteins involved in plasma osmotic pressure

plasma osmotic pressure

keeping water in blood

RBCs lack what?

nucleus (anucleate)

hormonal stimulus steps

1. hypothalamus

2. anterior lobe of the pituitary gland

3. endocrine glands

   stimulus: hormones from hypothalamus

   response: anterior lobe of pituitary gland secretes hormones that stimulate other endocrine glands to secret hormones

how does blood typing work? what is the importance?

its important to determine blood group of both donor and recipient

• blood is mixed with antibodies against common antigens

what is Rh factor?

Rh+ indicates presence of D antigen, comes from Rhesus monkey

what is hemolytic disease of the newborn?

occurs in Rh- mom and Rh+ baby

• Rh- mom exposed to Rh+ baby during first pregnancy

• second pregnancy: mom’s anti Rh antibodies cross placenta and destroy RBCs of Rh+ baby

what is this granulocyte?

neutrophils

neutrophils

• most numerous WBCs

• bacteria slayers

• ex. white stuff you see in your pimples, that is bacteria that has been engulfed by neutrophils

what is this?

eosinophil

eosinophil

plays a role in allergies and asthma

what is this?

basophil

basophil

inflammatory

what is this?

lymphocyte

lymphocyte

T lymphocytes and B lymphocytes

found in lymphoid tissue and spleen

T lymphocytes (T cells)

act against virus infected cells and tumor cells

B lymphocytes (B cells)

give rise to plasma cells, which produce antibodies

what is this?

monocyte

monocytes

leave circulation, enter tissues, and differentiate into highly mobile macrophages

what is hemostasis?

rapid series of reactions that stop bleeding

1. vascular spasm

2. platelet plug formation

3. coagulation

cAMP steps

1. hormone (1st messenger) binds receptor

2. receptor activates G protein

3. G protein activates adenylate cyclase

4. adenylate cyclase converts ATP to cAMP (2nd messenger)

5. cAMP activates protein kinases