Lecture 16 - The Cardiovascular System Flashcards
3 Main Components
- Heart - Muscular pump
- Blood Vessels - Conduits for blood to flow
- Blood - Fluid that circulates through the body and carries materials between cells
Cardiovascular Disease Examples
- Heart Attack
- Stroke
- Heart Failure
- Hypertensions
- Coronary artery disease
- Peripheral Artery Disease
- Myocarditis
Arteries
- Thick muscular walls
- Designed to handle the high pressures in arterial blood
Arterioles
- A bit less muscle
- Lots of innervation (nerves) to control smooth muscle contraction
Capillaries
- No muscle so there is no control over diameter or connective tissue
- can’t withstand high pressure
- high permeability ( for movement of fluid)
Nutrient, waste, fluid exchange at local level
Veinules
Main site of lymphocytes crossing from blood to lymph nodes
Veins
Thin walled, fairly muscular, for easy expansion and recoiling
Blood Vessles Differ by Velocity and Area
High velocity + small surface area = direct, rapid conductance of blood
Large surface area + Low Velocity = optimal exchange
Capillary
Cardiac output
Most amount of blood pumped by the heart per minute (heart rate x stroke volume)
Resting blood flow cardiac output
5 L/min
Exercise Blood Flow Cardiac Output
25.0 L/min (mostly in skeletal muscle)
Blood Movement for Veins
Against gravity - toward the heart
- Facilitated by the expansion of the thoracic cavity, contracting skeletal muscles and valves
Varicose Veins
- One way valves malfunction
- Allows backwards flow of blood and pooling
- Often in thigh and calf veins (Saphenous vein)
Heart Muscle
Myocardium - Involuntary and Autonomic
Neural Conduction of Myocardium
Gap junctions
- very fast
- contract as a unit
Metabolism of Myocardium
- Very high oxidatative capacity (35%)
- A lot of mitochondria to make the heart fatigue resistant
Atrioventricular Valves
- Mitral Valve
- Tricuspid Valve
Semilunar Valves
- Aortic Valves
- Pulmonary Valves
AV Valves Closing Sound
“LUB” - tricuspid and mitral valves closing
Semilunar Valves Closing
“DUB” - Caused by closure of pulmonary and aortic valves
Heart Valve Problems - Example (Stenosis)
Narrowing of a valve
Heart Valve Problems
- May be from birth
- Seriouseness varies
- Can cause fatigue and shortness of breath, exercise intolerance, or in more serious cases heart failure
Artificial Valve Issues
- Durability
- Clot formation
- Can get stuck
- Resistance to flow: Vulnerability to back flow or regurgitation
