Lecture 13 Flashcards
What 3 things is the cardiovascular system composed of?
Heart, blood vessels, blood
What is the heart?
Muscular pump
What are blood vessels?
conduits for blood to flow
What is blood?
Fluid that circulates through the body and carries materials between the cells
What are affiliated organs/tissues of the cardiovascular system?
- Lymph, cerebrospinal fluid (CSF), extracellular fluid
- Lymph & CSF vessels
- Kidney (erythropoietin, filtering)
- Spleen, thymus, tonsils (reservoirs for blood/immune cells)
- Lungs (O2, CO2 removal)
- Bone marrow (stem cell pool)
What does the lymphatic system do?
maintains fluid balance & supports immune
system
* Lymph nodes, lymphatic vessels, spleen, tonsils, & thymus
* Filters harmful substances from lymph & transports white blood
cells
* Lymphatic vessels return excess interstitial fluid & substances to
bloodstream i.e. balance between fluid intake & output
what does the cardiovascular system do?
Transports blood
What are some examples of cardiovascular disease?
- Coronary artery disease
- Stroke
- Heart attack (myocardial
infarction) - Heart failure
- Hypertension
- Diabetes
- Etc.
What is the continuous loops of blood flow?
- Deoxygenated blood returns to right side
of heart (enters right atrium) from venous
circulation - Atria receive blood
- Heart contracts, pumps blood to ventricles
- From right ventricle to lungs, then left
atrium - Oxygenated blood leaves left ventricle via
the aorta - Note the deoxygenated blood in the
pulmonary artery & the oxygenated blood
in the pulmonary vein
What are arteries characteristics?
Thick, muscular walls (smooth muscle) designed to handle high pressures
What are arteriole characteristics?
- A bit less muscle (pressures dropping)
- Lots of innervation to control vessel diameter through smooth muscle contraction (main
site of BP regulation)
What are capillaries characteristics?
- No muscle i.e. no control over diameter
- No connective tissue i.e. no ability to withstand high pressures
- Movement of fluid & solutes maximized
- Nutrients, waste, fluid exchange at local leve
What are venules characteristics?
- Main site of lymphocytes (white blood cells) crossing from blood to lymph nodes
What are veins characteristics?
- Thin-walled & fairly muscular for easy expansion & recoiling
What is cardiac output?
- The amount of blood pumped by the heart per minute
- A product of heart rate x stroke volume
What happens in veins?
Blood is moving against gravity, toward the heart by pressure gradient between left & right side of heart
What are veins facilitated by?
- Expansion of the thoracic cavity during breathing
- Contracting skeletal muscles
- Valves (prevent blood flowing backwards)
What are varicose veins?
- One-way valves malfunction
- Allow backwards flow of blood & pooling
- Generally occurs in superficial veins in thigh & calf (saphenous vein – longest vein in the body)
What is the heart made out of?
- Heart is made of cardiac muscle tissue (myocardium)
What is the neural input regarding the heart?
Involuntary and autonomic
What is the neural conduction regarding the heart?
gap junctions (very fast, contract as a
unit)
What is the hearts metabolism like?
Many mitochondria (~35% of volume compared to ~5% in skeletal muscle)
* Fatigue resistant (beats ~3 billion times over a lifetime)
How do heart valves control blood flow?
AV valves closing, Semilunar valves closing
What happens when AV valves close?
- “LUB” (1st heart sound)
- AV valves located between each atrium &
ventricle - Closure of tricuspid valve (right) & mitral
valve (left)
