Anatomy Exam 2

Plug Formation

1. vascular spasm, smooth muscle contracts, causing vasoconstriction

2. platelet plug formation, exposes underlying collagen, fibers, platelets adhere

   1. platelets release chemicals that make nearby platelets sticky, platelet plug forms (60 seconds)

3. coagulation, fibrin proteins form a mesh that traps RBCs and platelets, forming the clot (about an hour later)

phase 1 of fibrin formation 

intrinsic pathway: vessel endothelium ruptures, exposing underlying tissues (collagen) 

extrinsic pathway: tissue cell trauma exposes blood to tissue factor (protein) 

prothrombin activator 

phase 2 of fibrin formation

prothrombin (II) and thrombin (IIa)

phase 3 of fibrin formation

fibrinogen (I) (soluble), Fibrin (insoluble polymer), cross linked fibrin mesh

how many blood clotting factors (proteins) are there?

13

Calcium ions is the ____ factor

fourth

extrinsic pathway is the.. 

fastest, bypasses intrinsic and forms clot in 15 seconds 

PDGF- platelet derived growth factor

stimulates smooth muscle cells to divide to repair the blood vessel wall

VEGF- vascular endothelial growth factor

stimulates repair of endothelium

anticoagulant drugs

“blood thinners..” they do not thin the blood, instead decreases ability of blood to form a clot. 

aspirin 

inhibits thromboxane A2 formation blocking platelet plug formation. low doses of aspirin reduces chance of heart attacks by 50% 

heparin

used in hospospital for postperative patients and blood transfusions

warfarin

used in outpatient care to reduce risk of stroke in atrial fibrillation. a more potent version is the main ingredient in rat poison.

thrombocytopenia

platelet number is low

spontaneus bleeding in small vessels

normal movement = hemorrhage

small purple blotches on skin

caused by suppressed red bone marrow, often due to radiation or chemotherapy

hemophilia 

inherited bleeding disorders 

hemophilia A

77% of cases, caused by deficiency in clotting factor VIII, occurs primarily in males, females are carriers and asymptomatic

hemphilia B

second most common type, deficiency in clotting factor IX, occurs primarily in males, females are carriers and asymptomatic

hemophilia C

symptoms mild, causes by deficiency of factor XI, occurs in both males and females

main symptoms: painful, swollen joints due repeated bleeding into joint cavity

genetically engineered clotting factors are now available

impaired liver function 

results in decrease supply of clotting factors, can occur in cirrhosis (scarring) of the liver due to alcoholism or hepatitis 

thrombus

blood clot that forms in an undamaged blood vessel and may block blood vessel

occurs in heart, may lead to heart attack

occurs in a limb, can lead to tissue death and amputation

embolus (moving blood clot)

thrombus is freely moving in blood stream

if it gets stuck in blood vessel in the lung = pulmonary embolus

stuck in blood vessel in brain = cerebral embolus, which can cause stroke

Blood type AB

no antibodies, universal recipient

blood type B 

anti a antibodies, receives from B and O 

Blood type A

anti b antibodies, receives from A and O

Blood type O

anti a and b antibodies, universal donor

someone who is Rh+ can receive..

Rh- blood

a person who is Rh- can receive Rh+ blood how many times? 

ONCE, more than once leads to hemolysis

Rhesus hemolytic disease of the newbord (HDN)

caused by incompatibillity between an Rh- mother and her Rh+ fetus.

if RhoGAM not available, then..

13-14% of Rh- expectant mothers could become alloimmunized during an Rh- incompatible pregnancy

alloimmunity

when the body gains immunity against antigens of another individual of the same species

25% of fetuses.. 

need immediate treatment to avoid brain damage from excessive jaundice 

25% of fetuses..

would die

50% of fetuses..

would be mildly affected and not require treatment

O+ is distributed

38%

A+ is distributed 

34% 

B+ is distributed

9% o

O- is distributed

7%

A- is distributed

6%

AB+ is distributed 

3% 

B- is distributed

2%

AB- is distributed

1%

size of the heart?

a fist

shape of heart? 

snow cone 

weight of heart?

less than a pound

what is the heart enclosed in?

mediastinum

what does heart rest on?

upper surface of diaphragm

heart is surrounded by? 

lungs 

what does the apex of the heart point to?

left hip

what is where the apex contacts the chest wall called?

PMI - point of maximal intensity

heart is enclosed in a double walled sac called the

pericardium

outer fibrous pericardium 

tough, dense CT, provides protection, is an anchor, and prevents overfilling 

middle serous pericardium is composed of how many layers?

2

parietal layer

lines inner layer of the fibrous pericardium

visceral layer (epicardium)

continuum of parietal layer, covers eternal surface of heart

between the parietal and visceral layers is the.. 

pericardial cavity, which contains serous fluid to lubricate membranes 

pericarditis

inflammation of pericardium

pericarditis is caused by?

bacterial infection

what does pericarditis do?

impedes production of fluid, causes friction between membranes + sticking + pain + impedes heart activity

how many layers does the heart wall consist of? 

3 

epicardium

same as visceral layer of serous pericardium

myocardium

bulk of heart, composed of cardiac muscle that contracts

endocardium

shiny white sheet of epithelial cells that lines heart chambers and covers valves. it is continous with the endothelial lining of blood vessels

the heart has how many chambers? 

4 

superior section of heart:

2 atria

inferior section of heart:

2 ventricles

what is the atria?

receiving chambers for blood returning to the heart from

1. the body via systemic circulation

2. the lungs via pulmonary circulation

the atria is.. 

small, thin walled 

blood enters right atrium via..

superior vena cava, inferior vena cava, and coronary sinus

blood enters left atrium via..

right/left pulmonary veins (from lungs)

pulmonary pump=

to heart

systemic pump = 

everywhere else 

what are ventricles?

discharging chambers

what do ventricles contain?

irregular muscle ridges called trabaculae carneae, and muscle bundles called papillary muscles

ventricles are..

the pumps of the heart that propel blood

right ventricle..

pumps blood into pulmonary circulation 

left ventricle..

pumps blood into systemic circulation

blue =

deoxygenated

red =

oxygenated

in the systemic circuit.. 

arteries carry blood away from the heart, veins carry blood to the heart 

in pulmonary circuit..

arteries carry blood to the heart, veins carry blood away from the heart

right side of heart..

pump for pulmonary circulation

sends oxygen poor, carbon dioxide rich blood to lungs

left side of heart..

pump for systemic circulation

atrioventricular valves (AV) 

located between atria and ventricles, there are 2 

what does AV prevent?

backflow of blood into atria when ventricles contract

“Lub” sound of heart

closing of bicuspid and tricuspid valves

“dub” sound of heart

closing of aortic and pulmonary valves

anatomy of cardiac muscles

striated, Z discs, and A and I bands (thick myosin, thin actin)

T-tubules (wider and fewer)

sarcoplasmic reticulum, but no terminal cisternae

cardiac muscle cells are.. 

shorter than skeletal muscle cells 

fatter than skeletal muscle cells 

branched 

how are cardiac muscle cells interconnected?

through intercalated discs and anchored together by desmosomes

what kind of junctions are in cardiac muscle cells and what do they allow?

gap junctions, allow ions to pass through and transmit depolarizing current across heart

resting membrane potentials in autorhythmic cells is..

unstable, reduced membrane permeability to potassium, and increased membrane permeability to sodium

action potentials of autorhythmic cells reach a threshold of? 

-40mv 

first step of action potentials in autorhythmic cells

pacemaker potential: slow depolarization is due to both the opening of sodium channels and the closing of potassium channels. membrane potential is never a flat line

second step of action potentials in autorhythmic cells

depolarization: the action potential begins when the pacemaker potential reaches threshold (-40mv). depolarization is due to calcium influx through calcium channels

third step of action potentials in autorhythmic cells

repolarization: due to calcium channels inactivating and potassium channels opening. allows potassium efflux, which brings membrane potential back to its most negative voltage

when does repolarization occur? 

when there is a decrease in calcium permeability, and when there is an increase in potassium permeability 

what happens at the end of repolarization?

potassium channels close, and slow depolarization begins again

first step of sequence of excitation

the sinoatrial (SA) node (pacemaker) generates impulses

second step of sequence of excitation

the impulses pause (.1 s) at the atrioventricular (AV) node

third  step of sequence of excitation

the AV bundle connects the atria to the ventricles