lecture 7 Flashcards
(20 cards)
What are the primary functions of the human cardiovascular system?
Distribution of O2 and nutrients, elimination of metabolic wastes, hormone transport, regulation of body temperature, pH, and fluid volume, and protection against blood loss and infection
Includes plasma proteins, platelets, antibodies, and WBCs.
What is the cardiac cycle?
All events associated with blood flow through the heart during one complete heartbeat, including systole (contraction) and diastole (relaxation)
Systole refers to the phase when the heart contracts and pumps blood, while diastole is when the heart relaxes and fills with blood.
What is cardiac output?
Volume of blood pumped by each ventricle in one minute, calculated as CO = heart rate (HR) x stroke volume (SV)
HR is the number of beats per minute, and SV is the volume of blood pumped out by a ventricle with each beat.
Define intrinsic cardiac conduction system.
A network of noncontractile (autorhythmic) cells that initiate and distribute impulses to coordinate depolarization and contraction of the heart
Gap junctions ensure the heart contracts as a unit.
How does the autonomic nervous system (ANS) regulate heart rate?
The ANS modifies the heartbeat through the cardioacceleratory center (sympathetic) and cardioinhibitory center (parasympathetic) located in the medulla oblongata
The sympathetic nervous system increases heart rate and force of contraction, while the parasympathetic nervous system decreases heart rate.
What are the two main types of control over cardiac output?
Intrinsic controls and extrinsic controls
Intrinsic controls originate within the heart, while extrinsic controls involve the nervous system.
What is the role of baroreceptors?
Baroreceptors monitor blood pressure and provide feedback to adjust heart rate and blood vessel diameter
They are located in the carotid sinuses and aortic arch.
What is the relationship between blood flow, blood pressure, and resistance?
Blood flow (F) is directly proportional to the blood pressure gradient (ΔP) and inversely proportional to peripheral resistance (R): F = ΔP/R
Increased pressure increases flow, while increased resistance decreases flow.
What are the short-term and long-term controls of blood pressure?
Short-term controls involve neural and hormonal mechanisms altering peripheral resistance; long-term controls involve renal regulation altering blood volume
Short-term adjustments help respond to immediate changes, while long-term adjustments stabilize blood pressure over time.
What are common cardiovascular problems?
Angina pectoris, myocardial infarction, arrhythmias, tachycardia, bradycardia, congestive heart failure
These conditions can lead to inadequate blood circulation and other serious health issues.
What is angina pectoris?
Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium
It indicates that the heart muscle is not receiving enough oxygen.
What is myocardial infarction?
Prolonged coronary blockage resulting in areas of cell death repaired with noncontractile scar tissue
Commonly known as a heart attack.
Define tachycardia.
Abnormally fast heart rate (>100 bpm)
If persistent, tachycardia may lead to fibrillation.
Define bradycardia.
Heart rate slower than 60 bpm
It may result in inadequate blood circulation or be a desirable outcome of endurance training.
What is congestive heart failure?
A progressive condition where cardiac output is so low that blood circulation is inadequate to meet tissue needs
Often caused by coronary atherosclerosis, persistent high blood pressure, or multiple myocardial infarcts.
What is hypertension?
Sustained elevated arterial pressure of ≥130 and/or ≥80 mm Hg
Prolonged hypertension can lead to heart failure, vascular disease, renal failure, and stroke.
What is hypotension?
Low blood pressure, with systolic pressure below 100 mm Hg
It can be a sign of poor nutrition or indicate conditions such as Addison’s disease.
What are the three main sources of resistance in blood flow?
- Blood viscosity
- Total blood vessel length
- Blood vessel diameter
These factors influence the friction blood encounters as it flows.
What is the role of the vasomotor center?
A cluster of sympathetic neurons that oversee changes in blood vessel diameter, maintaining vasomotor tone
It receives inputs from baroreceptors, chemoreceptors, and higher brain centers.
What is the renin-angiotensin mechanism?
A hormonal response to decreased arterial blood pressure that leads to vasoconstriction and increased blood volume through aldosterone and ADH
It helps restore blood pressure to normal levels.
