University of Iowa - Human Physiology - Exam 3 | Quizlet

Blood, heart, blood vessels

The cardiovascular system consists of

Blood

Transport medium fluid and cells suspended in fluid

Heart

Pump that drives the circulation of blood

Blood vessels

Tubing that conducts blood through circulation from one part of the body to another

5.5 L

Average blood volume

Erythrocytes, leukocytes, platelets, plasma

Blood consists of

Erythrocytes

Red blood cells

Leukocytes

White blood cells

Platelets

Cell fragments important for blood clotting

Plasma

Fluid component of blood

Water (90%)

"Stuff" dissolved in water - electrolytes, nutrients, gasses, plasma proteins

45%

How much of blood consists of formed elements (erythrocytes, leukocytes, platelets)

55%

How much of blood consists of plasma

Sodium, potassium, calcium

Electrolytes found in plasma

Glucose, amino acids, fatty acids, lipoproteins

Nutrients found in plasma

Oxygen, carbon dioxide

Gasses found in plasma

Clotting

Fibrinogen functions in

Transport lipid soluble substances

Transport proteins functions in

Plasma proteins

What differs between ISF and plasma

Nucleus, organelles

Red blood cells do not have...

Squeeze through capillaries

Purpose of flexible membranes on RBCs

Hemoglobin

Found only in red blood cells

Globin chains, heme

Composition of hemoglobin

Heme

Ion containing group that helps carry oxygen in the blood (can carry 4 total)

Carry oxygen (also binds carbon dioxide, hydrogen, carbon monoxide)

Primary role of hemoglobin

Erythropoesis

Erythrocyte production

Bone marrow

Where does erythropoiesis occur

Multipotent stem cells

RBCs come from

Erythropoietin (hormone)

Stimulates erythropoiesis

120 days

RBCs survive about

2-3 million cells/second

Rate that RBCs are replaced

Spleen

Removes most of old erythrocytes

Anemia

Below-normal oxygen carrying capacity of the blood

Hematocrit

Anemia is diagnosed by measuring

Causes of anemia

Dietary deficiencies, blood loss, bone marrow failure, hemolytic anemia

Megakarocyte cell

Platelets come from

Thrombopoeitin

Hormone produced by the liver that increases the number of megakarocytes and therefore increases platelet production

Hemostasis

Prevents blood loss from a broken blood vessel

Vascular spasm

Formation of a platelet plug

Blood coagulation

Three steps of hemostasis

Vascular spasm

Reduces blood flow through a damaged vessel

Formation of a platelet plug

Platelets aggregate on contact with exposed collagen in damaged wall of the vessel

Platelets release ADP which causes surface of nearby circulating platelets to become sticky

Intrinsic and extrinsic

Two possible pathways of blood clot formation

Intrinsic pathway

Contact of platelets with foreign surface (ie. collagen)

Extrinsic pathway

Activator molecule from damaged endothelial cells

Final outcome of blood clot formation

Fibrinogen (soluble) --> fibrin (insoluble)

Pulmonary and systemic

Two circuits of the heart

Right ventricle

Pulmonary trunk

Pulmonary arteries

Lungs

Release carbon dioxide

Pick up oxygen

Pulmonary veins

Left atrium

what circuit

Pulmonary circuit

Left ventricle

Aorta

Whole body (tissues)

Vena cavas

Right atrium

what circuit

Systemic circuit

Left atrium, right atrium, left ventricle, right ventricle

Four chambers of the heart

Atria

Receive blood from veins

Ventricles

Pump blood into arteries

Systemic circuit

Right atrium

Pulmonary circuit

Left atrium

To lungs

Right ventricle

To body

Left ventricle

AV valves, semilunar valves

Two sets of valves

AV valves

Allow flow from Atria to ventricles and prevents backflow

Semilunar valves

Allow flow from ventricles to great arteries, prevents backflow

Passive valves

Open and close by pressure difference in chambers

Lub dub

Caused by closure of valves

Lub

Caused by closure of AV valves

Dub

Caused by closure of semilunar valves

Right atrium

Right AV valve

Right ventricle

Pulmonary semilunar valve

Pulmonary trunk and arteries

Lungs (pulmonary circuit)

Deoxygenated blood enters right side through the vena cava

Left atrium

Left AV valve

Left ventricle

Aortic semilunar valve

Aorta

Tissues (systemic circuit)

Oxygenated blood enters left side through pulmonary veins

Systole and diastole

The cardiac cycle consists of 2 parts

Systole

Ventricles contracting

Diastole

Relaxing and filling

Isovolumetric contraction

Ejection

Systole sequence of events

Isovolumetric contraction

Ventricles contract, but no blood ejected

Blood pressure rises above pressure in atria

AV valves shut (start of systole)

Ejection

Blood pressure in ventricles exceeds pressure in arteries

Semilunar valves open, blood flows out of ventricles, causing pressure in ventricles to fall

Isovolumetric relaxation

Rapid filling

Atrial contraction

Diastole sequence of events

Isovolumetric relaxation

Pressure in ventricles drops below arterial pressure

Semilunar valves prevent backflow of blood (shut)

No change in ventricular volume

Rapid filling

Pressure in ventricles falls below atrial pressure

AV valves open, allowing blood to flow into ventricles

Autorhythmic, contractile

Two specialized types of cardiac muscle cells

Autorhythmicity

Heart beats via

Autorhythmic cells

Do not contract

Initiate AP's and spread impulse throughout heart

Contractile cells

99% of cardiac muscle cells

Do mechanical work of pumping

Normally do not initiate own action potentials

SA node

AV node

Bundle of His

Right and left bundles branches

Purkinje fibers

Gap junctions

Myocardial cells

Electrical activity of heart sequence

Pacemaker

SA node functions as

EKG

Record of overall spread of electrical activity through heart

P

QRS

T

Stereotypical waveform

P wave

Atrial depolarization

QRS wave

Ventricular depolarization

T wave

Ventricular repolarization

Coronary vessels

Provide blood supply to heart during diastole

Coronary artery disease (CAD)

Leading cause of death in the United States

3 major steps of hemostasis

1. vascular spasm

2. formation of a platelet plug

3. blood coagulation (clotting)

what are the 2 heart valves

atrioventricular valve (AV) and semilunar valve (SV)

a heart beats via

auto rhythicity

2 specialized types of cardiac muscle cells

autorhythmic cells and contractile cells

autorhythmic cells

do not contract - initiate AP's and spread impulse throughout heart

contractile cells

99% of cardiac muscle cells, do mechanical work of pumping, normally don't initiate own action potentials

why is there an AV node conduction delay

to ensure the atria have fully contracted & emptied blood into the ventricles before the ventricles contract -- this delay is crucial for efficient blood flow & prevents premature ventricle contractions

coronary circulation

flow of blood to and from the tissues of the heart - delivered via coronary vessels

coronary vessels

supply the heart muscle with its blood supply (during diastole)

striated muscles

skeletal & cardiac

unstriated muscle

smooth

voluntary muscle

skeletal

involuntary muscle

cardiac & smooth

a muscle is defined as

number of muscle fibers bound by connective tissue

are muscle fiber and muscle cell that same thing

yes