Week #12 Flashcards
What is a closed circulatory system?
Requires vessels to contain fluids that circulate around organism
ex. mammals (humans)
What is an open circulatory system?
Does not require vessels to contain fluids that circulate around organism
ex. mosquitos and grasshoppers
What are the three steps of gas exchange?
Ventilation, Circulation, and Respiration
What is the overview of the circulatory system?
- Transport of nutrients, removal of wastes
- Exchange of gases (O2 & CO2)
What are the 7 functions of the vertebrae circulatory system?
- Transport O2 from lungs to tissues; CO2 from tissues to lungs
- Distribute nutrients from digestive system to body’s cells
- Transport waste and toxic substances to liver, where many are detoxified, and to kidneys for excretion
- Distribute hormones from organs to tissues on which they act
- Regulate body temperature, achieved partly by adjustments in blood flow
- Prevent blood loss with clotting mechanism
- Protect body from bacteria and viruses by circulating antibodies and white blood cells
What is blood?
Type of connective tissue composed of fluid matrix called plasma and formed elements
What is plasma?
Water, proteins, nutrients, hormones, etc.
55%
What is buffy coat?
White blood cells (leukocytes) and platelets
5%
What is hematocrit?
Red blood cells (erythrocytes)
45%
What is the normal blood composition for females and males?
Females: 37% - 47% hematocrit
Males: 42% - 52% hematocrit
Blood is composed primarily of WHAT?
PLASMA!
What is the order of arteries from large to small?
Aorta –> Arteries –> Arterioles
What is the order of veins from large to small?
Inferior/Superior Vena Cava –> Veins –> Venules
What are some characteristics of arteries?
(Oxygenated blood away from heart)
Thickly coated walls, circular, high pressure
What are some characteristics of veins?
(Deoxygenated blood to heart)
Thin walls, oblong
What are valves?
Prevent backflow (open/close), blood flow caused by muscle contraction
T/F - In the calf muscle example, when the calf is relaxed valves are open?
False, they are closed. They are open when the muscle contracts.
What is the venous pump?
Helps return blood to heart; Skeletal muscle contractions and one-way venous valves
What is the overview of blood flow/circulation?
Superior/Inferior Vena Cava –> Right Atrium –> Tricuspid Valve –> Right Ventricle –> Pulmonary Valve –> Pulmonary Artery –> Lungs –> Pulmonary Vein –> Left Atrium –> Mitral/Bicuspid Valve –> Left Ventricle –> Aortic Valve –> Aorta –> Rest of Body –> Repeats, Back to Vena Cava
What are the two pairs of valves?
Atrioventricular (AV) and Semilunar valves
What are Atrioventricular (AV) valves?
Maintain unidirectional blood flow between atria & ventricles; Tricuspid = On right; Bicuspid / mitral = Left
What are Semilunar (half-moon) valves?
Ensure one-way flow out of ventricles to arterial systems; Pulmonary valve at exit of RV; Aortic valve at exit of LV
How long does the cardiac cycle take?
0.8 Seconds
What is blood pressure?
Valves open and close, force of blood pushing against the walls of your arteries
Ventricles relaxed and filling (diastole, denominator)
Ventricles contracted and pumping (systole, numerator)
Normal ~ 120/80
What is the sound your heart makes when heard with a stethoscope?
“Lub-dub”
Lub – AV valves closing
Dub – Semilunar valves closing
What is the heart’s conduction system?
Heart contains “self-excitable” autorhythmic fibers
What is the most important node of the heart’s conduction system?
Sinoatrial (SA) node
What is the Sinoatrial (SA) node?
“Pacemaker”; Right atrium wall; Autonomic nervous system can modulate rate
Where does the heart’s conduction system impulse end?
Heart Apex (pointed tip of heart)
Where is each SA depolarization transmitted?
To left atrium and to right atrium and atrioventricular (AV) node
What is the AV node?
Only pathway for conduction to ventricles; Electrical pulse spreads through atrioventricular bundle
What are Purkinje fibers?
Directly stimulate the myocardial cells of both ventricles to contract
What is the conduction pathway of the heart?
Sinoatrial node & Bachmann’s bundle –> Atrioventricular node –> His Bundle –> Left/Right Bundles –> Purkinje Fibers –> Ventricles Contract
What is an electrocardiogram?
(ECG / EKG) Records electrical activity
Draw a typical ECG with labels
Rate Yourself
What is the P Wave?
First peak (P) produced by depolarization (contraction) of atria (atrial systole); Depolarization/Contraction of Atrium
What is the QRS Wave?
Second, larger peak (QRS) produced by ventricular depolarization (contraction) (ventricular systole); Depolarization/Contraction of Ventricle
What is the T Wave?
Last peak (T) produced by repolarization of ventricles (ventricular diastole) (relaxation); Repolarization/ Relaxation of Ventricles
