Final: Circulatory System Slides Flashcards
Components of cardiovascular system
Closed system that consists of the heart, blood vessels, and blood
Functions of cardiovascular system (3)
- Heart pumps blood (to deliver it)
- Blood vessels provide path for blood to travel
- Blood carries nutrients to organs and picks up wastes
What does it mean the cardiovascular system is closed?
Blood always contained in the blood vessels; and the blood itself is not exchanged (only the contents)
Pulmonary circuit
Short distance; communication between heart and lungs; delivers deoxygenated blood from heart to lungs
Systemic circuit
Long distance; moves nutrients throughout the body; delivers oxygenated blood from heart to body
Blood coming to cells is _____ oxygenated and blood leaving cells is ____ oxygenated
Richly, poorly
Blood coming to lungs is _____ oxygenated and blood leaving lungs is _____ oxygenated
Poorly, richly
What happens when cardiac muscles of heart contract?
Blood physically ejected from heart as muscles work against a load/weight (the blood)
What are the atria?
Receiving chambers; where blood enters
What are the ventricles?
Pumping chambers; blood leaves the heart from here to the blood vessels
What are valves?
Flaps of connective tissue that guide blood in the right direction in the heart; prevent blood from flowing backwards
Location of tricuspid valve
Between right atrium and right ventricle
Location of bicuspid valve
Between left atrium and left ventricle
Location of pulmonary semilunar valve
Between right ventricle and pulmonary trunk
Location of aortic semilunar valve
Between left ventricle and aorta
Main blood vessels in heart (5)
Superior vena cava, inferior vena cava, pulmonary trunk, pulmonary veins, aorta
Superior vena cava function
Bring deoxygenated blood from all structures above diaphragm to the right atrium
Inferior vena cava function
Bring deoxygenated blood from all structures below diaphragm to right atrium
Pulmonary trunk function
Take deoxygenated blood from right ventricle to lungs (branches off, one branch for each lung)
Pulmonary veins function
Bring back oxygenated blood from lungs to left atrium
Aorta function
Deliver oxygenated blood from left ventricle to body (biggest blood vessel; delivers blood all over)
Path of blood through the heart
Poorly oxygenated blood from body enters heart through SVC or IVC - right atrium - tricuspid valve - right ventricle - pulmonary semilunar V - pulmonary trunk - lungs - richly oxygenated blood enters heart through pulmonary veins - left atrium - bicuspid valve - left ventricle - aortic semilunar valve - aorta - body (then repeat)
What is ventricular diastole? Which valves are open/closed?
Ventricles are relaxed and filling with blood
- Bicuspid and tricuspid valves are open
- Aortic and pulmonary valves are closed
What do you hear in a heart beat?
Valves closing: first bicuspid and tricuspid, then aortic and pulmonary (one diastole and one systole)
What is ventricular systole? Which valves are open/closed?
Ventricles contracting to eject blood
- Bicuspid and tricuspid valves closed
- Aortic and pulmonary valves open
What initiates heart activity (how does it contract)?
Specialized pacemaker cells that generate their own electrical activities
What structures of the heart do pacemaker activities go through (in order)?
- Sinoatrial node (starts process)
- Atroventricular node
- Bundle of His (reaches apex)
- Bundle of branches
- Purkinje fibers
What direction do ventricles contract in?
Bottom to top
Order of contraction
Atria then ventricles
Location of sinoatrial node (SA)
Right atrium
Location of atrioventricular node (AV)
Interatrial septum
Location of bundle of His
Interventricular septum
Location of Purkinje fibers
Ventricular walls
How do right and left ventricles contract simultaneously?
Lots of gap junctions in cardiac muscle fibers (allow movement of action potentials)
How do we know the heart is working properly?
Electrocardiogram (minimally invasive) used to record electrical activities of the heart
How does an electrocardiogram work?
Patient connected to electrodes - EKG/ECG machine picks up collective action potential
Parts of one trace of electrocardiogram
P wave: atria contraction/depolarization
QRS complex: ventricular contraction/depolarization
T wave: ventricular relaxation/repolarization
Types of blood vessels (5) and order of flow after leaving heart
Arteries - Arterioles - Capillaries - Venules - Veins
Which structures correspond to which parts of ECG?
SA and AV: P wave
Bundle of His: dip before P wave
Purkinje fibers: QRS complex
What are arteries?
Strong elastic vessels that carry blood away from the heart and branch into smaller arterioles
What are veins?
Carry blood back to the heart, have thinner walls than arteries, branch into smaller venules
Layers of arteries and veins (4)
Tunica externa, tunica media, tunica interna/intima, lumen
What is the tunica externa?
Connective tissue with elastic and collagen fibers
Tunica media structure and function
Made of smooth muscles; mediates vasoconstriction and vasodilation
Tunica interna/intima structure and function
Made of simple squamous epithelium (endothelium); provide smooth surface for blood to pass through (minimize friction)
Structural differences between arteries and veins (3)
Arteries have smaller lumen and thicker tunica media; only veins have valves; arteries are high pressure because they receive blood directly from the heart
Capillary function and structure
Smallest diameter blood vessels
Made of endothelial layer only; have slits (thinness facilitates gas diffusion/exchange)
Site of gas exchange with cells
What is involved in microcirculation?
Arterioles (oxygen-rich), capillaries (gas exchange), venules (oxygen-poor)
In [gas] exchange between capillaries and cells, which substances go where?
O2 and glucose go from capillary to cell, and CO2 goes from cell to capillary
Veins have ___ ____ and therefore hold the majority of the blood
Low pressure
How do skeletal muscles help veins return blood to the heart?
Skeletal muscle contraction squeezes veins and helps them push blood back to heart (working against gravity)
Blood composition
Fluid connective tissue made of cellular components (erythrocytes, leukocytes, platelets) suspended in plasma fluid
Plasma composition
Water, proteins that exert osmotic pressure, minerals and electrolytes
Plasma proteins (and their functions)
Albumins: transport proteins
Globulins: immune function
Fibrinogen: clotting function (minimize blood loss)
Erythrocyte function and location of synthesis
Transport gases (O2, CO2) in body; produced in bone marrow
Erythrocyte structure
Biconcave discs, lack organelles, short life span (~120 days), packed with hemoglobin (bound to iron); formation depends on folic acid and B12 vitamins
What regulates erythrocytes?
Erythropoietin, a hormone released by the kidney that acts on bone marrow to replace/release red blood cells as needed
