Chapter 13 - Circulatory and Respiratory Systems Flashcards
What is the human cardiovascular system composed of?
1) Muscular, four chambered heart
2) Blood vessels
3) Blood
Describe the movement of blood:
- Blood is pumped into the aorta which branches into a series of arteries
- Arteries branch into arterioles and then into microscopic capillaries
- Exchange of gases, nutrients, and cellular waste products occur via diffusion across capillary walls
- Capillaries converge into venues and back into veins that carry deoxygenated blood back toward the heart
- From the heart the blood is pumped into the lungs to exchange CO2 for O2
- Oxygenated blood returns to heart to be pumped once more
What does the heart do?
It is the driving force of the circulatory system
What does the right vs. left side do?
Right side:
- Pumps deoxygenated blood into pulmonary circulation (toward lungs)
Left Side:
- Pumps oxygenated blood into systemic circulation (throughout body)
What are the upper and lower chambers called? Describe each:
Upper = Atria
- Thin-walled
Lower = Ventricle
- Muscular
- Left > right muscular because it must generate force that propels systemic circulation and pumps against higher resistance
What is a result of increased systemic resistance?
Left ventricle becomes hypertrophied (enlarged) which can lead to congestive heart failure and other cardiovascular diseases
Describe the flow of blood through the heart:
- Blood returns from the body through the right atrium
- Through the tricuspid valve into the right ventricle
- Through the pulmonary semilunar valve into the pulmonary arteries to the lungs
- Blood runs from lungs through pulmonary veins into the left atrium
- Through the mitral valve into the left ventricle
- Finally, out through aortic semilunar valve into systemic circulation
Where is the atrioventricular valve located? What does it do?
Located between the atria and ventricles on both sides of the heart
- Prevents back flow of blood into the atria
Where is the tricuspid valve located? How many cusps?
Located on the right side of the heart
- Has 3 cusps
Where is the mitral valve located? How many cusps?
Located on the left side of the heart
- Has 2 cusps
Where are the semilunar valves located?
Located between the left ventricle and aorta and between the right ventricle and the pulmonary artery
What creates the “lub-dub” sound of the heart?
The successive closing of the atrioventricular and semilunar valves
How is the heart’s cycle divided?
Into 2 alternating phases:
1) Systole: Phase where ventricles contract, forcing blood out of the heart and into the pulmonary system
2) Diastole: Phase where cardiac muscle relaxation during which blood drains into all 4 chambers
Describe blood pressure:
- Systolic blood pressure measures the pressure in a patients blood vessels when the ventricles are contracting
- Diastolic blood pressure measures the pressure during cardiac relaxation
Define cardiac output:
Total volume of blood the left ventricle pumps out per minute
Cardiac Output = Heart Rate (beats/min) x Stroke Volume (V of blood pumped out of L-ventricle/contraction)
How is the heart rate controlled?
Cardiac muscles contract rhythmically without stimulation from nervous system, producing impulses that spread through its internal conducting system
Where does an ordinary cardiac contraction originate and is regulated by?
- How does the impulse spread?
- Where does the pulse arrive?
- How is the impulse carried?
- What does the strong contraction do?
The sinoatrial node (SA) which is a small mass of specialized tissue located in the wall of the right atrium
- Spreads impulse through both atria stimulating them to contract simutaneously
- Arrives ar atrioventricular node (AV) which conducts the impulse to the rest of the heart, allowing time for atrial contraction and for ventricles to fill with blood
- Impulse carried through bundle of His (AV bundle) which branches to the L/R and through Purkinje fibers located in the ventricular walls to stimulate a strong contraction
- Forces blood out of the heart
What modifies the rate of the heart? How?
ANS
- PNS innervates heart via vagus nerve to decrease HR
- SNS innervates heart via cervical and upper thoracic ganglia to cause increases in HR
- Adrenal medulla exerts hormonal control via epinephrine recreate to increase HR
What are the 3 types of blood vessels? Describe each:
1) Arteries
- Thick walled, muscular, elastic vessels the support oxygenated blood flow away from the heart
- Except for the pulmonary artery (deoxygenated blood from heart to lungs)
2) Veins
- Thin walled, inelastic vessels that carry deoxygenated blood toward the heart
- Except for the pulmonary vein (oxygenated blood from lungs to heart)
- Depends on compression from skeletal muscle
- At odds with gravity (valves)
3) Capillaries
- Smallest diameter (RBC single filed)
- Single layer of epithelial cells
- Exchanges gas, nutrients, and waste
What is the lymphatic system?
Second circulatory system; transports excess interstitial fluid (lymph) to the cardiovascular system to keep fluid in the body constant
What is the smallest lymphatic vessel? What do they do?
Lacteals
- Collect fats in the form of chylomicrons from villi in the small intestine and deliver to the blood stream, by passing the liver
What are lymph nodes?
Swellings along lymph vessels containing phagocytic cells (lymphocytes) that filter the lymph, removing and destroying foreign pathogens and particles