Lecture 15/16: Cardiovascular System (Part 1) Flashcards
What organs/tissues are affiliated with the cardiovascular system
- extracellular fluid lymphatics (like circulatory system but for extracellular fluid)
- Kidney and spleen
- liver
- lungs
- bone marrow
The right side of the cardiovascular system___
returns deoxygenated blood to heart
The left side of the cardiovascular system___
carries oxygenated blood away from heart
Arteries bring blood ____ the heart
bring blood away from heart
Veins bring blood ____ the heart
bring blood to the heart
What is unique about the pulmonary circuit
- veins bring oxygenated blood to heart and arteries bring deoxygenated blood away
Where is most blood held in the body
- on route to heart in systemic veins and venules
Characteristics of arteries
-thick muscular walls, handle high pressures in arterial blood
Characteristics of Arteriolds
- smaller diameter to regulate blood flow
- less muscle but lots of innervation to control smooth muscle contraction
- main site of blood pressure regulation ***
What are characteristics of capillaries
- no muscle
- does not regulate its dismeter or withstand high pressures
- involved in movement of fluid and solutes (maximize the movement)
- nutrient, waste, fluid exchange at local level
What are characteristics of veins
- thin walled, muscular for easy expansion and recoiling
How does velocity an area influence blood vessels
- high velocity and small surface area = direct, rapid conductance of blood
- low velocity and large surface area= optimal exchange
How do veins move blood against gravity towards heart
pressure gradient between left and right side of heart by:
- expansion of the thoracic cavity during breathing
- contracting skeletal muscles
- valves (preventing blood flowing backwards)
What are Vericose veins
- one way valves malfunction
- allow backwards flow of blood and pooling
- generally in superficial veins in thigh and calf
- generally does not effect overall blood flow to heart
What type of tissue is the heart made out of?
myocardium
How does cardiac muscle differ from skeletal muscle?
Nerval input: involuntary, autonomic
Neural conduction: gap junctions, very fast and contract like unit (skeletal muscle has fibre recruitment)
Metabolism: Very high oxidative capacity
- lots of mitochondria, about 35% of volume
- fatigue resistant
How is blood flow controlled in the heart
- valves
- atria always contract together
- lub sound = AV valves closing
- ventricles contract together
- dub sound = semilunar valves contracting
What is stenosis?
Narrowing of valve, vary in terms of seriousness but can cause fatigue, shortness of breath, exercise intolerance and in more serious cases heart failure
What are some issues with artificial valves
- clot formation, requires consistent anticoagulant therapy
- get stuck
- resistance to flow, vulnerability to back flow/regurgitation
Note: almost 300,000 replacemnts per year and mad eof very durable material
What is systole
- contraction, highest BP usually 120/80
What is diastole
- relaxation, lowest BP, usually 120/80, 80 is the pressure next pump must overcome
What is a very basic overview of cardiac cycle
- contraction of atria
- contraction of ventricles
- rest when neither is contracting
What are electrical signals in heart propagated by?
- nodes (SA and AV)
- nerves (bundle of His, bundle branches, purkinge fibres)
- intercalated disks
What is tachycardia?
- abnormal SA node firing (too fast)
