PT 405 E2 Study Guide

What is the difference between autocrine hormones, paracrine hormones, and pheromones?

autocrine - have a local effect on same cell

paracrine - have a local effect on other cell types without being transported in blood

pheromones - secreted into the environment and modify behavior and physiology

What are the 3 methods that hormones are regulated by?

- action of a substance other than a hormone or endocrine gland
- neural control of an endocrine gland
- control of secretory activity of one endocrine gland by hormone or neurohormone secreted by another endocrine gland

What is the difference in how monoamines + peptides and steroids + thyroid hormone are transported in the blood?

monoamines + peptides - hydrophilic so they can mix with the blood plasma

steroids + thyroid hormone - must bind to transport proteins

What are the differences between a bound and unbound hormone?

bound - attached to transport protein to prolong half-life and protect it from enzymes and kidney filtration

unbound - leaves capillary to reach target cell and the half-life is a few minutes

How do peptides and catecholamines activate cellular activity?

bind to surface receptors to initiate a second messenger system to activate the G protein and initiate a cascade of intracellular reactions

How do steroids and thyroid hormones activate cellular activity?

pass through cell membrane to bind to a receptor on the cell nucleus to activate or inhibit the gene for a metabolic enzyme of other protein

What is the difference between exocrine and endocrine glands?

exocrine - ducts carry secretion to a surface or organ cavity

endocrine - have no ducts and release hormones into tissue fluids and intracellular effects alter target cell metabolism

Where do the nervous and endocrine systems interact?

pituitary gland and hypothalamus

What is the main difference between the anterior and posterior pituitary gland?

anterior - receives hormones from the hypothalamus and sends signals via blood vessels

posterior - an extension of the hypothalamus and sends signals via neurons

What two hormones does the posterior pituitary gland secrete?

- oxytocin
- antidiuretic hormone

What is the key difference between the "communication" between the hypothalamus and the two lobes of the pituitary gland?

anterior - hormones travel via the hypothalamo-hypophyseal portal system in the blood and receive releasing or inhibiting hormones

posterior - hormones are released in response to nervous system signals; neuroendocrine refelxes

What is the direct and indirect effect of GH?

direct - bind to receptors and causes changes within the cells

indirect - causes liver and skeletal muscle to produce somatomedins and produce somatomedins (IGFs)

What hormone:
- stimulates uptake of amino acids for protein synthesis
- breaks down fats
- stimulates glycogenesis
- promotes bone and cartilage growth
- regulate blood levels of nutrients

- stimulate uptake of amino acids
- stimulate break down of fats for energy and stimulates glycogenesis for glucose sparing
- promotes bone and cartilage growth
- regulates blood levels of nutrients after meals and periods of fasting

How is the secretion of GH regulated?

releasing - GHRH is secreted by hypothalamus in response to low blood glucose, stress, etc

inhibiting - GHIH (somatostatin) is secreted in response to high blood gluocose

What doe GnRH stimulate the secretion of?

- FSH
- LH

What do LH and FSH do?

regulate the production of genes and reproductive hormones

What does prolactin do?

plays a role in milk production

What are the 3 steps of the release of thyroid hormones T3 and T4?

1. hypothalamus secretes TRH
2. anterior pituitary releases TSH
3. thyroid releases T3 and T4

What 2 hormones inhibit TRH and TSH secretion?

- T3
- T4

What causes the release of ACTH?

CRH from the hypothalamus

What 3 things does ACTH do?

regulates response to stress to stimulate the adrenal cortex via
- cortisol secretion
- aldosterone secretion
- melanin production

What does ADH (vasopressin) do?

targets kidneys to increase water retention and reduce urination

What does oxytocin do?

produced in the hypothalamus to help with labor contractions and lactation

What does the pineal gland do?

produces serotonin in the day and converts it to melatonin at night
- may regulate timing of puberty

Which gland undergoes involution after puberty?

thymus

What is the largest endocrine gland?

thyroid

What type of cells secrete T3 and T4?

follicular cells (simple cuboidal)

What hormone(s)?
- increases metabolic rate
- increases O2 consumption
- increases heat production (calorigenic effect)
- increases heart rate and contraction strength
- increases respiratory rate
- stimulates appetite and breakdown of carbs, fats, and proteins

T3 and T4

What type of cells produce calcitonin?

C (parafollicular) cells

What does calcitonin do?

decreases blood calcium to promote calcium deposition and bone formation, especially in children

33-40% of (T3/T4) is converted to (T3/T4) because (T3/T4) is more potent

- T4
- T3
- T3

What hormone(s)?
- increases blood calcium levels
- promotes synthesis of calcitriol
- increases calcium absorption
- decreases urinary secretion
- increases bone resorption

PTH

The sympathetic nervous causes the adrenal medulla to secrete what 2 hormones?

- epinephrine
- norepinephrine

What do the three layers of the adrenal cortex produce?

zona glomerulosa - mineralcorticoids, (aldosterone for Na+ retention and K+ secretion)

zona fasciculata - glucocorticoids (cortisol)

zona reticularis - sex steroids (DHEA)

What hormone(s)?
- stimulates fat and protein catabolism
- gluconeogenesis
- releases of fatty acids and glucose into te blood
- anti-inflammatory

cortisol

What does large amounts of cortisol inhibit the release of?

- ACTH
- CRH

Does the pancreas function more as an exocrine of endocrine gland?

exocrine - 98% of organ produces digestive enzymes

What do the peancreatic islet cells release?

beta - insulin

alpha - glucagon

delta - somatostatin

What hormone(s)?
- stimulate glucose and amino acid uptake in cells
- stimulate glycogen, fat, and protein synthesis for storage

insulin

What causes glucagon to be secreted?

low carb and high protein diet or fasting

What hormone(s)?
- stimulates glycogenolysis
- fat catabolism to release FFAs
- promotes absorption of amino acids for gluconeogenesis

glucagon

What does somatostatin do?

acts as a paracrine hormone to inhibit the secretion of insulin and glucagon

What does inhibin do?

inhibit FSH secretion

What does relaxin do?

increases flexibility of pubic symphysis

What hormone(s)
- stimulates the development of the female reproductive system and physique
- regulates menstrual cycle
- prepares mammary glands for lactation

estradiol and progesterone

What hormone(s)?
- stimulates the development of male reproductive system and physique
- sustains sperm production and sex drive

testosterone

What is the endocrine function of the heart?

releases ANP in response to high blood pressure to decrease volume volume and pressure by increasing sodium and water loss by kidneys

How is vitamin D3 converted to calcitriol?
include the organs

- skin produces vitamin D3
- liver converts vitamin D3 to calcidiol
- kidney converts calcidiol to calcitriol

What organ converts angiotensinogen to angiotensin II?

kidneys

What does the placenta do?

secrete estrogen and progesteron to regulate pregnancy, and stimulate the development of fetus and mammary glands

What is the difference between up and down regulation?

up - stimulus causes an increase in the number of receptors to make the cell more sensitive

down - stimulus causes a decrease in the number of receptors to make the cell less sensitive

What is the difference between a synergistic, permissive, and antagonistic effect?

synergistic - two or more hormones act together to produce an overall effect

permissive - one hormone enhances the target organ's response to a second hormone

antagonistic - one hormone opposes the action of another

Briefly describe the 3 stages of general adaptation syndrome

1. Alarm reaction - increases in EPI and NE levels
2. Glycogen stores are gone so cortisol levels increase and there's an adverse effect on the immune system
3. Fat reserves are gone and loss of homeostasis

What is an endemic goiter and how does it affect TH and TSH?

enlarged thyroid gland that can cause hypo- or hyperthyroidism due to a dietary iodine deficiency
- no TH so no feedback
- increase in TSH

Describe the 3 main symptoms of diabetes

polyuria - increased urination

polydispsia - increased thirst

polyphagia - increased appetite

What is the difference between nonspecific resistance and specific resistance?

nonspecific - general defense mechanisms; including external barriers, inflammation, and fever

specific - fights off a specific pathogen via cell-mediated or antibody-mediated immunity

Describe the relationship between lymphatic capillaries, vessels, nodes, trunks. and ducts

capillaries - closed at one end and have valve like flaps; form vessels

vessels - contain valves and drains toward the trunks away from tissues

nodes - distributed along the vessels to filter lymph

trunks - combines vessels and contains the jugular, subclavian, bronchomediastinal, intestinal, and lumbar trunks

ducts - drains tissues of body and move lymph into major veins

Describe the 3 antigen-presenting cells (APCs)

macrophages - form from monocytes

dendritic cells - in epidermis, mucous membranes, and lymphatic organs

reticular cells - contribute to stroma of lymph organs

What are mucosa-associated lymphatic tissues (MALT)?

lymphatic tissue that is in passages that are opened to the exterior

What are lymphatic nodules?

masses of lymphocytes that congregate in response to pathogens

What occurs at the primary lymphatic organs and what are examples?

T and B cells become immunocompetent

red bone marrow and thymus

What occurs in the secondary lymphatic organs and what are examples?

immunocompetent cells populate

lymph nodes, tonsils, and spleen

Describe the 3 types of tonsils

palatine - pair at the posterior margin of the oral cavity

pharyngeal (adenoids) - single tonsil on the wall of the pharynx

lingual - pair at the roof of the tongue

Describe the cortex and medulla of the thymus

cortex - contains lymphocytes and macrophages

medulla - reticular epithelial cells that produce thymic homrones and contains Hassall's corpsucles

How do the T cells, dendritic cells, epithelial cells, and macrophages function together in the cortex of the thymus?

- immature T cells come from red bone marrow to proliferate and mature
- dendritic cells assist in maturation
- epithelial cells "educate" the T cells and produce hormones
- macrophages eat non-surviving T cells

How many T cells survive and enter the thymic medulla?

2%

What are Hassall's corpuscles in the thymic medulla?

layers of flat cells that degenerate and contain keratohyalin granules

What is the largest single mass of lymphatic tissue in the body?

spleen

What does the hilus of the spleen contain?

- blood vessels
- lymphatic vessels

What is the difference between the white and red pulp of the parenchyma in the spleen?

white - contains lymphatic tissue (lymphocytes and macrophages)

red - venous sinuses filled with blood and splenic cords (Billroth's)

What are 3 external barriers of the innate immune system?

- skin - contains lactic acid to help with perspiration
- mucous membranes - contain lysozyme to destroy bacterial walls
- subepithelial areolar tissue - barrier of hyaluronic acid

Which two cells perform phagocytosis?

- neutrophils
- macrophages

What are the neutrophils role in innate immunity?

- arrive before macrophages to enter infected tissue
- begin degranulation - lysozymes go into tissue fluid
- respiratory burst - creates toxic chemicals

What are the macrophages role in innate immunity?

formed from monocytes and arrive at site of infection to ingest larger particles

What is the role of basophils and mast cells in innate immunity?

- promote inflammation
- increase WBC mobility and action by releasing histamine (vasodilator) and heparin (anticoagulant)

What are 2 roles of eosinophils in innate immunity?

- reduce inflammation by breaking down chemicals produced by the basophils and mast cells
- kill parasites

What 2 things do NK cells do in innate immunity?

- lyse tumor and virus-infected cells
- recognize whole classes of cells

What are interferons and what 2 things do they do?

secretions by virus-infected cells that act as a generalized protection
- stimulate neighboring cells to produce antiviral proteins
- activate NK cells and macrophages

What are complement proteins?

proteins in the blood that must be activated by pathogens

When C3 is split in the complement system, what are the 3 pathways?

classical - requires antibody and is specific immunity

alternate - nonspecific immunity

lectin - nonspecific immunity

What does the C3a pathway of the complement system cause?

inflammation

What 3 things does the C3b pathway of the complement system cause?

- immune clearance
- phagocytosis
- cytolysis

What is opsonization?

complement proteins "flag" the microorganism for phagocytosis

What 3 things happen in the classical pathway?

1. Ag-Ab complex forms on pathogen surface
2. Reaction cascade
3. C3 dissociates into C3a and C3b

What 4 things happen in the alternate pathway?

1. C3 dissociates into fragments C3a and C3b
2. C3b binds to pathogen surfaces
3. Reaction cascade and autocatalytic effect
4 C3 dissociates into C3a and C3b

What 3 things happen in lectin pathway?

1. lectin binds to carbohydrates on pathogen surfaces
2. reaction cascade
3. C3 dissociates into C3a and C3b

What percentage of lymphocytes are NK cells?

10-15%

How does a NK cell attack a cell?
(perforin, granzymes, etc)

1. NK cell releases perforins to form a hole in enemy cell
2. granzymes from NK cell enter hole
3. granzymes degrade enemy cell's enzymes
4. enemy cell dies via apoptosis
5. macrophage eats enemy cell

What are the 3 major processes of inflammation?

- mobilization of defenses
- containment and destruction of pathogens
- tissue clean up and repair

During the mobilization of defenses, what are the 3 things secreted by damaged cells, basophils, and mast cells?

- kinins
- histamines
- leukotrienes

What 2 things does kinins, histamine, and leukotrienes cause?

- stimulate vasodilation, leading to hyperemia
- stimulates permeability of blood capillaries

What are the 2 ways that leukocytes are deployed during the mobilization of defenses during inflammation?

margination - selectins cause leukocytes to adhere to blood vessel walls

diapedesis (emigration) - leukocytes squeeze between endothelial cells into tissue space

What 4 things happen during the containment and destruction of pathogens stage of inflammation?

- fibrinogen clots to trap pathogens
- heparin prevents clotting at injury site
- chemotaxis attracts leukocytes
- neutrophils respond

What do neutrophils do during the containment and destruction of pathogens stage of inflammation?

- eat cells and cause respiratory burst that secretes cytokines
- cytokines recruit more macrophages and neutrophils
- macrophages and T cells secrete CSF to stimulate leukopoiesis

Describe the 3 stages of a fever

1. onset - body temperature rises
2. stadium - body temperature remains at new set point
3. defervescence - body temperature returns to normal

What is the difference between cellular and humoral immunity?

cellular - T cells directly attack against foreign/diseases host cells; intracellular

humoral - antibody-mediated cells indirectly attack pathogen; extracellular

What is the difference between natural active immunity and artificial active immunity?

natural active - infection of or direct exposure to antigen

artificial active - result of vaccination

What is the difference between natural passive immunity and artificial passive immunity?

natural passive - acquires antibodies from mother; temporary

natural artificial - injection of antibodies; temporary

What is the difference between foreign and self antigens?

foreign - introduced from outside

self - produced by body to differentiate between self and outside

Where to T and B cells originate?

red bone marrow