MCAT BIO Lecture 7

the most force

not attached to bone

when the ventricles contract

the relaxation of the entire heart then the atria contracting

** ~ parasympathetic nervous system**

slows the rate of heart contractions
- the SA node individually contracts faster, but the vagus makes it slow down

(also increases digestive activity in the intestines)

located in the ventricles

the AP is spread by them throughout both ventricles via gap junctions;

allows for a more unified, and stronger, contraction

pacemaker of the heart; contracts regularly

located in the RA

causing them to contract

and at the same time hits the AV node to contract

- the AV node is slower to contract => a delay that lets the atria finish contracting and squeezing their blood into the ventricles

located all down the WALL SEPARATING the VENTRICLES

connects to the Purkinje fibers

stretch as they fill with blood

arterioles are wrapped by smooth muscle

only site of gas and nutrient exchange - not across arterioles or venules

csA of veins is 4 times bigger than arteries

veins act as a blood reservoir, holding 64% during rest

follows Q = Av

the total cross-sectional area of all capillaries > csA of a single aorta or a few arteries

to compensate, they have skeletal pump valves

pulmonary veins, the most

skeletal muscles inervated by the phrenic nerve

deliver oxygen to the blood, expel CO2

warm, moisten, and clean the air

pharynx = throat

trachea = windpipe

prevents food from entering the trachea

trachea splits into two bronchi, which become bronchioles, which lead to alveoli

breathing

b/c the cilia of the nasal cavity are made from MT's

those same RBC's release CO2, which diffuses into the alveolus and is expelled upon exhalation

110 mm Hg

pp of CO2 = 40 mm Hg

which is inside the erythrocytes

oxygen + hemoglobin = oxyhemoglobin


each of the 4 iron atoms in hemoglobin can bind with an O2 mlcl

release of one O2 => faster release of the others

Increase in PCO2, [H+], temperature;

shift to the right indicates a **decrease of hemoglobin's affinity for oxygen**

the % of hemoglobin that is bound with oxygen at various partial pressures of oxygen

in the arteries of a normal person, the oxygen saturation is 97%

small fluctuations in oxygen pressure have little effect

40 mm Hg

the enzyme that governs bicarbonate formation

CO2 + H2O = HCO3 - + H+


*carbon dioxide mostly comes in the form of bicarbonate*

high concentration of H+ => acidosis

when [CO2] gets too high, breathing increases

shifts the OXYGEN dissocaitaion curve to the LEFT, as O2 remains avidly bound and is slower to dissociate from hemoglobin

collects excess interstitial fluid in tissue and returns it to the blood

protein and large particles that cannot be taken up by capillaries are removed by the lymph system

also monitors blood for infection

an open system - fluid enters at one end and comes out the other

which makes sure lymph flow only goes one way

flow is propelled by smooth muscle contractions or skeletal muscle squeezing from the outside adjacent

made up of plasma, WBC's, and RBC's

hematocrit = percentage of RBC's = usually 35-50%

proteins in the blood that transport FA's and steroids

also regulate osmotic pressure

antibodies

clotting protein

plasma from which fibrinogen has been removed = serum

they have no organelles, not even a nucleus

=> they don't reproduce or undergo mitosis

**deliver O2, remove CO2**

opposite of RBC's - contain organelles, but don't contain hemoglobin

protect the body from foreign invaders

erythrocytes lose their nucleus while still in the marrow

tiny cells without a nucleus

**the coagulation process starts with them**

only defects in DNA cause hereditary diseases

one of two or more alternative forms of a gene

occupy a specific position on a specific chromosome

lymphatic capillary that absorbs dietary fats in the villi of the small intestine

protein R has used ATP, not the other protein

increased fluid in body tissues

major coagulant;

has nothing to do with the immune system

transports FA's and steroids

From Great Spain

how efficiently the substance can be reabsorbed

lower Tm = will pass into urine more than substance with higher Tm (like glucose)

equilibrium

N! (N factorial)

e.g. 3! = 3x2x1 = 6