Kardio Fun Time

Random 1

100

Design of circulatory system

Closed circuit: pulmonary and systemic circulations

Circulating fluid: blood

Operated by pressure differences valves determine direction of flow

Arterial: away

Veins: return

200

Flow of blood in the cardiovascular system is…

Directly proportional to the pressure gradient inversely proportional to the resistance to flow 

Flow=∆pressure/resistance

Resistance=1/radius^4 (resistance is inversely proportional to radius4)

300

Erythrocytes (RBCs)

Transport oxygen and CO2 

Shape allows for the cells to bend slightly in order to go through capillaries 

400

CO2 transport

1. Co2 diffuses out of cells into systemic capillaries
2. Only 7% of the co2 remains dissolved in plasma
3. Nearly a fourth of the co2 binds to hemoglobin
4. 70% of the co2 load is converted to bicarbonate
5. HCO3 enters the plasma in exchange for Cl
6. At the lungs dissolved co2 diffuses out of the plasma
7. Law of mass action co2 unbinds from hemoglobin and diffuses out of the rbc
8. The carbonic acid reaction reverses pulling HCO3 back into the rbc and converting it back to co2

500

SA node

Pacemaker of the heart

Origin of electrical signal

Connected by fibers to transmit electrical signals quickly

Random 2

100

Pulmonary circulation

Right atrium: receive return blood from rest of body, pumps into right ventricle

Right ventricle: "pumping chamber" pushes blood into pulmonary circulation

Lungs: blood is transported to lungs where it is oxygenated and CO2 is released

Pulmonary veins: oxygenated blood travels through the pulmonary veins in order to reach systemic circulation

200

arteries

Elastic systemic arteries are a pressure reservoir that maintains blood flow during relaxation

300

Leukocytes (WBCs)

Lymphocytes: produce specific immune responses

Monocytes: phagocytes develop into macrophage

Neutrophils: mobile phagocytes that ingest foreign substances

Eosinophils: provide toxic compounds directed pathogens

Basophils: mast cells 

400

Ventricular contraction

Systole the AV valves remain closed to prevent blood flow backward into the atria

Pressure rises above atria and aorta and the ventricle contracts

Valves prevent backflow

Increase in cytosolic ca

500

Conducting system of the heart

1. Sa node depolarizes
2. Electrical activity goes rapidly to av node via internodal pathway
3. Depolarization spreads slowly across atria, conduction slows through av node
4. Depolarization moves rapidly through ventricular conducting system to the apex
5. Depolarization wave spreads upwards from the apex

Random 3

100

Systemic circulation

Left atrium: blood from pulmonary circulation collects in here

Left ventricle: blood collected in left atrium is then moved into here to be pushed out into the aorta 

Aorta: carries blood to other arteries so the oxygenated blood can reach the entire body

200

Resistance in individual tissues

Resistance is offered by arterioles that supply a given organ important in regulation of tissue flow

300

Hematocrit

Normal range: 40-45 percent

400

Ventricular relaxation

Diastole

Mitral valve is open to allow blood to move from left atria to ventricle 

Semilunar valves prevent blood that has entered the arteries from flowing back into the ventricles during relaxation 

Decrease in cytosolic ca

500

Cross bridge cycling:

1. Ca levels increase in cytosol
2. Ca binds to troponin
3. Troponin-ca complex pulls tropomyosin away from G-actin binding site
4. Myosin binds to actin and completes power stroke
5. Actin filament moves

Random 4

100

Arterioles

Smallest arteries 

Site of variable resistance-- change in diameter to accommodate pressure changes

 

200

Total peripheral resistance 

Total resistance offered by entire arteriolar network important in regulation of arterial blood pressure

300

Hemoglobin

Composed of four protein globin chains 

Centered around a heme group

Each heme group consists of a porphyrin ring with an iron atom in the center 

The iron is responsible for binding to O2

400

Contractile cells

Striated fibers organized into sarcomeres responsible for generating tension that causes heart muscle contraction

500

SA node

Sets the pace of heart beat (~70 bpm) 

AV node (50bpm) and purjunkie fibers (25-40 bpm) can act as pacemakers under some conditions

Random 5

100

Capillaries

Smallest blood vessels site of exchange between blood and cells

200

Components of blood

Plasma 

red blood cells

Platelets

White blood cells

300

Gas exchange and transport

1.  O2 enters the blood alveolar-capillary interface
2. o2 is transported in blood dissolves is plasma or bound to hemoglobin in RBCs
3. o2 diffuses into cell
4. Co2 diffuses out
5. Co2 is transported dissolved and bound to hemoglobin
6. Co2 enters alveoli at alveolar-capillary interface

400

Autorhythmic cells

Initiate the electrical signal for contraction

Smaller than contractile cells 

Do not have organized sarcomeres

500

Internodal pathway from SA to AV

Routes the direction of electrical signals so the heart contracts from apex to base av node delay is accomplished by slower conduction signals through nodal cells