Lec Exam 1

hormones

* Messenger of the endocrine system 


* Secreted by exocytosis 
* Produced in minute amounts by a collection of specialized epithelial cells
* Secreted directly into blood or extracellular fluid 
* Acts on specific tissues of the body called target tissues 
* Most are protein based or steroids 

protein derived hormone

water soluble

receptors typically membrane bound

steroid derived hormone

fat soluble

can cross cell membrane

receptors typically in cytosol or nucleus

nervous system vs endocrine system

the nervous system uses electrical impulses to send messages through neurons while endocrine glands use hormones to send messages to the target cells through the bloodstream

membrane bound receptors

protein derived hormones bind to them

\n Activation of 2nd messengers

\n Response time: fast

intracellular receptors

steroid hormones bind to them \n

Response time: slower than membrane bound \n

activate gene expression by binding to steroid receptors, proteins in the cytoplasm that, when activated, act as factors that initiate transcription

prolactin

abbrev: PRL

location: anterior pituitary

structure: protein

target: mammary glands

response: causes milk production

conditions: secreted at the end of pregnancy; excess production can be a sign of breast cancer in men

growth hormone

abbrev: GH

location: anterior pituitary

structure: protein

target: mainly muscle and connective tissues

response: a. a. uptake for protein & glycogen synthesis, growth in tissues, stimulates muscle and bone growth

conditions: (decreased amounts) pituitary dwarfism, and pituitary giants (gigantism) and acromegaly (abnormal amounts)

thyroid stimulating hormone

abbrev: TSH

location: anterior pituitary (tropic)

structure: protein

target: thyroids gland

response: increase thyroid hormone production

conditions: hypothyroidism, hyperthyroidism

\
act via cAMP mechanisms 

adrenocorticotropic hormone

abbrev: ACTH

location: anterior pituitary (tropic)

structure: protein

target: adrenal cortex

response: increased hormone secretion from the adrenal cortex (especially glucocorticoids)

conditions: cushings

\
act via cAMP mechanisms 

follicle stimulating hormone

abbrev: FSH

location: anterior pituitary (tropic)

structure: protein

target: follicles in ovaries, seminiferous tubules (males)

response: follicle maturation and estrogen secretion in ovaries, and sperm cell production in testes

conditions: infertility, menstrual difficulties in women, low sex drive in men, and early or delayed puberty in children

\
act via cAMP mechanisms 

androgens

location: adrenal cortex

* Female: testosterone
* Male: progesterone

structure: steroid

target: many tissues

response: some secondary sex characteristics in females

conditions: persistent acne, hirsutism, androgenic alopecia

epinephrine and norepinephrine

Epi - 80%; Nor- 20%

location: adrenal medulla

structure: protein

target: heart, blood vessels, liver, fat cells

response: fight or flight response

conditions: hypertension, depression, anxiety, post-traumatic stress disorder

\
act via cAMP mechanisms 

glucagon

location: pancreas

structure: protein

target: liver

response: associated with sympathetic response to low levels of glucose in the blood. Stimulates breakdown of glycogen stores in usable glucose

conditions: hypoglycemia, diabetes, acute or chronic pancreatitis

\
act via cAMP mechanisms 

testosterone

location: testes

structure: steroid

target: most body tissues

response: secondary sex characteristics, libido, sperm production

conditions: hypogonadism

tropic hormones

\n TSH, ACTH, FSH, LH

tropic hormone function

target other endocrine glands

luteinizing hormone

abbrev: LH

location: anterior pituitary (tropic)

structure: protein

target: ovaries and testes

response: ovulation and progesterone production in ovaries, testosterone synthesis, and support for sperm cell production in testes

conditions: abnormal development, sexual dysfunction, and infertility

\
act via cAMP mechanisms 

antiduretic hormone

abbrev: ADH

location: posterior pituitary

structure: protein

target: nephrons on kidney

response: causes the nephrons to reabsorb water instead of losing it as urine

conditions: copious urination can lead to diabetes insipidus; can be inhibited by alcohol

\
DAG (Directed acyclic graphs) IP3 Second messenger system 

oxytocin

location: posterior pituitary

structure: protein

target: uterus and mammary glands

response: causes uterine contraction during birth and milk ejection, high during ejaculation and orgasm

conditions: autism, schizophrenia, mood and anxiety disorders

\
DAG (Directed acyclic graphs) IP3 Second messenger system 

thyroid hormone

abbrev: TH

location: thyroid

structure: protein

target: most cells in the body

response: increases metabolism, essential for growth

conditions: low TH (hypothyroidism) can lead to cold, weight gain, and fatigue, can be treated w/ steroids, associated with high TSH levels; high TH (hyperthyroidism) loss of weight, high energy, and increased ocular pressure, and can sometimes die from heart issues, treatment is to remove or kill portions of thyroid, associated with low TSH levels

calcitonin

location: thyroid

structure: protein

target: bone

response: decreases Ca2+ by decreasing osteoclast activity

conditions: medullary thyroid cancer, brittle bones

\
act via cAMP mechanisms 

parathyroid hormone

abbrev: PTH

location: parathyroid

structure: protein

target: bones, kidneys, small intestine

response: raise levels of blood calcium by breaking down bone, causes reabsorption of calcium by kidney, and causes intestines to absorb more calcium and vitamin D

conditions: is sometimes removed when thyroid is removed

\
act via cAMP mechanisms 

aldosterone

location: adrenal cortex

structure: steroid

target: nephrons of the kidney – sodium ion resorption

response: controls nephron tubule permeability and reabsorbs salts based on need, thus water will follow the salt back in  by osmosis

conditions: Hyperaldosteronism

cortisol

location: adrenal cortex

structure: steroid

target: most tissues in the body

response: increase fat and protein breakdown, inhibit immune inflammatory response

conditions: cushings

insulin

location: pancreas

structure: protein

target: especially liver, skeletal muscle, fat tissue

response: increases intake of glucose by cells

conditions: diabetes mellitus, obesity, cardiovascular disease

\
Usually, part of the parasympathetic response after a meal when a lot of glucose is present in the blood

estrogen and progesterone

location: ovaries

structure: steroid

target: most body tissues

response: secondary sex characteristics, menstrual cycle

conditions: menstrual problems, menopause, premature menopause

islet vs acinar cells

**islet**

produces hormones (e.g., insulin and glucagon)

endocrine (secrete hormones or other products directly into the blood)

\
**acinar**

produce digestive enzymes

exocrine (secrete their products through ducts opening onto an epithelium)

up regulation

the number of receptors increases in response to rising hormone levels, making the cell more sensitive to the hormone and allowing for more cellular activity

\
ex. increase in uterine oxytocin receptors in the third trimester of pregnancy, promoting the contraction of the smooth muscle of the uterus

down regulation

the number of receptors decreases in response to rising hormone levels allowing for decreased cellular activity

\
ex. insulin receptors may be down regulated in type 2 diabetes

affinity

the extent or fraction to which a drug binds to receptors at any given drug concentration or the firmness with which the drug binds to the receptor

pineal gland

* Sits right above corpora quadrigemina 
* Secretes melatonin 

pituitary gland

* Connected to hypothalamus 
* In sella turcica of sphenoid bone 

thyroid gland

two lobes are connected by a bridge 

located in neck

parathyroid

* Connected to thyroid 
* 4 of them 

thymus

* Located in the chest cavity 
* Extremely important at birth and young infants 
* Takes over for immunity 
* Can be as large as from the heart to thyroid gland 


* By adulthood it deteriorates 

heart

* Not technically an endocrine organ 
* Secretes hormone to regulate BP 

stomach and intestine lining

* Secretes hormones that help metabolism and digestion 
* Not considered endocrine 

adrenal glands

Located on top of the kidneys 

pancreas

* Mix of endocrine and exocrine gland 


* Endocrine: insulin, glucagon 
* Exocrine: more digestive related 


* Epithelial glands 

ovary

* Mix of endocrine and exocrine gland 
* Epithelial glands 


* Exocrine: ova 
* Endocrine: estrogen and progesterone 

testes

* Mix of endocrine and exocrine gland 
* Epithelial glands 


* Exocrine: spermatozoa  
* Endocrine: testosterone 

eicosanoids

* Derived from cell membranes (arachidonic acid) 


* Leukotrienes and prostaglandins 
* Also called paracrine substances 
* Not considered true hormones by some 

cell response

* Opening or closing of ion channels. 


* Stimulate enzyme synthesis within cells. 
* Activates or deactivates enzymes within the cell. 
* Can cause phosphorylation of enzymes within the cell. 
* mRNA synthesis and direct gene activation. 
* Can influence or affect mitosis. 

permissiveness

* One hormone cannot exert its full effects unless another hormone is present 


* Congenital hypothyroidism 

synergism

* When two or more hormones affect a target cell and their effects are amplified 


* Ex. After you eat blood sugar begins to drop so body secretes glucagon and epinephrine to cause liver to break down glycogen and raise blood sugar levels 

antagonism

* When one hormone opposes the action of another 


* Ex. High blood sugar – insulin; low blood sugar – glucagon 
* PTH vs calcitonin  

humoral regulation

* Insulin and glucagon 
* Aldosterone and potassium 

neural regulation

* Posterior pituitary 
* Hypothalamus 
* Activation of adrenal medulla  

hormonal regulation

Anterior pituitary (tropic hormones) 

primary hypothyroidism

TH decrease → TRH and TSH increase

secondary hypothyroidism

TH decreases and TSH decreases → TRH increases

tertiary hypothyroidism

TH, TSH, TRH decrease

primary hyperthyroidism

TH increases → TSH and TRH decreases

secondary hyperthyroidism

TRH decreases → TH and TSH increase

tertiary hyperthyroidism

TH, TSH, and TRH increase

Cushing’s (primary hypercortisolism)

Cortisol high → ACTH low

secondary hypercortisolism

cortisol high → ACTH high

addison’s disease ( primary adrenal insufficiency)

Cortisol low → ACTH high

secondary adrenal insufficiency (hypopituitarism)

Cortisol low → ACTH low

plasma

about 55% blood volume

about 92% H2O 8% proteins, gases, nutrients

formed elements of blood

45%

RBCs

WBCs

Platelets

plasma proteins

Albumin (60%)

* Maintains osmotic pressure in capillaries, carries other molecules through the blood

\
Globulin (36%)

* Transport binding proteins and some types of antibodies

\
Fibrinogen (4%)

* Important for blood clotting

erythrocytes

RBCs

45% of blood by volume

4-6million/ μL

They do not have a nucleus

Short life span 120 days (about 4 months) max

Small biconcave discs

They can bend to pass through capillaries

Larger surface area to capture oxygen and CO2

too few RBCs

tissue hypoxia

too many RBCs

viscous blood

hemoglobin

Oxygen carrier

Each erythrocyte has enough hemoglobin to carry 1 billion molecules of oxygen

Has 4 atoms of iron to bind to oxygen

* Women 12-16 g/dL 


* Men 13-18 g/dL 

hematopoiesis

Takes place in red bone marrow

Production is stimulated by erythropoietin (EPO)

platelets

150k-400k/ μL

Fragments of megakaryocytes

Short lived (abt 10 days)

Help with clotting

leukocytes

WBCs

**N**ever **L**et **M**onkeys **E**at **B**ananas (most to least abundant)

Less than 1% of blood

Are true cells

Includes different subtypes

* Neutrophils
* Basophils
* Lymphocytes (B and T cells)
* Monocytes (macrophages)

leukopoiesis

WBC production

Hormones and other stressors can stimulate their production in bone marrow

leukopenia

insufficient amount of WBCs

Autoimmune disease

Severe stress

Cancer treatment

Bone marrow deficiency

leukocytosis

Too many WBCs

Infections (especially bacterial)

Inflammatory disease

Leukemia

Mono

neutrophils

Most abundant WBC

Band cell stage – immature version of neutrophil

50-70%

Nucleus has between 3-5 lobes

Clinical significance

* Increase in number during acute bacterial infections such as appendicitis
* Most bacteria are extracellular pathogens
* Increased number = neutrophilia
* Decreased number = neutropenia

eosinophils

1-4% of WBC

Nucleus often bi-lobed or figure 8 shape

Cytoplasm dyes red in presences of dye eosin

Clinical significance

* Increased eosinophils may indicate allergic conditions or parasitic infections (trichinosis)
* eosinophilic esophagitis

basophils

< 1% of WBC Large U or S shaped nucleus stains blue in presences of basic dyes Can release histamine and heparin Clinical significance * Release histamine to promote inflammation and heparin to prevent clotting * Very important for immune response

lymphocytes

20-30% of WBC

Smallest WBC

Nucleus is spherical

Clinical significance

* Increased amounts seen with almost all general immune system responses
* T-cells – contact killing, generally attack viruses
* B-cells – often more active against bacteria, antibody production

monocytes

3-8% of WBC

Largest of WBC

Nucleus generally kidney shaped

When they leave blood, they are macrophages

Clinical significance

* Voracious phagocyte that acts in long-term cleanup of chronic infections (mononucleosis, tuberculosis)
* Increased amounts during viral infections and chronic infections

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hemostasis

1) Constriction of the blood vessel

2) Formation of a temporary “platelet plug."

3) Activation of the coagulation cascade

4) Formation of “fibrin plug” or the final clot

reticulocyte

* often found in hypoxic situations 


* Immature RBCs 

hazards of cross matching blood types

agglutination which can cause:

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red blood cell destruction

renal failure

shock

death

vascular spasm

narrowing of the arteries caused by a persistent contraction of the blood vessels

platelet plug formation

Major stimulus is when platelets are exposed to underlying connective tissue 

\
the process where a platelet plug forms to prevent further loss of blood from a damaged vessel

coagulation

adhesion and aggregation of platelets, as well as deposition and maturation of fibrin.

clot retraction

Actomyosin proteins pull edges of cut together 

\
increases clot density and decreases clot size

fibrinolysis

* Fibrin mesh that trapped RBCs needs to be dissolved once vessel is healed 
* If not dissolved it can get stuck somewhere and cause a clot (pulmonary embolism – blood clot stuck in lungs) 

RBC counts

* Women 4.2-5.4 million/µL 


* Men 4.6-6.2 million/µL 

WBC counts

5000 - 10000 cells/μL

hematocrit

aka PCV (packed cell volume) percentage of blood that is cells (usually RBCs) 

* Women 37-48% 
* Men 45%-52% 

\
referred to as H&H in clinical settings (hematocrit and hemoglobin)

\
clinical significance

\
Anemia: a reduction of the delivery of O2 to tissues caused either by having too few RBCs or not enough hemoglobin in the circulating blood. \n

Polycythemia - is an abnormally high density of RBC, can lead to overexertion of the heart and vessel clogging

differential WBC count

measures the percentages of each type of leukocyte present

\
Neutrophils: 50-70% \n –Basophils: 0.5-1.0% \n –Eosinophils: 1-4% \n –Lymphocytes: 20-30% \n –Monocytes: 3-8%

blood functions

Distribution – oxygen delivery, waste transport, hormones \n

Regulation – body temp, pH, fluid volume \n

Protection – preventing blood loss, immune functions

oxygen rich

bright red blood

oxygen poor

dark red blood

average amount of blood in people

5-6L in adult males

4-5L in adult females

danger of Rh factor

If Rh- mother 

* Develops Rh+ fetus (75-80%) 
* Few complications during first pregnancy 
* Mom develops antibodies against Rh+ because mom and baby blood mix at birth 
* During second pregnancy usually Rh+ again 
* Rh antibodies can cross the placenta and interact with Rh+ fetus and agglutinate fetus blood (stroke, embolism, renal failure) 
* Can lead to death of baby and mom 
* Shots of Rhogam block body reacting to Rh factor 

blood typing

Serological testing

* Antibody–antigen reaction 


* Shows up as clotting 

thromboembolytic disorders

* Clotting in undamaged vessels 
* Thrombus is a clot in a vessel 
* Embolus is a clot that has broken free 


* TPA (thromboplastin activator) breaks up clots and doctors use it to treat clots in strokes 

bleeding disorders

Thrombocytopenia 

* Scarcity of thrombocytes 

\
Hemophilia  

* Blanket term for wide variety of bleeding disorders 
* Most are genetic 
* Related to lack of various clotting factors 

systemic circuit

blood pumped out to body (all tissues)

\
left ventricle through arteries into capillaries in tissues

pulmonary circuit

shunts de-oxygenated blood from the heart to the lungs to be re-saturated with oxygen before being dispersed into the systemic circulation