Body Fluids and Circulation Flashcards
From where to where do arteries transport blood? What type of blood do they transport?
- From the heart to the rest of the body
- Carry mostly oxygenated blood
From where to where do veins transport blood? What type of blood do they transport?
- From the rest of the body to the heart
- Carry mostly deoxygenated blood
From where to where do capillaries transport blood? What type of blood do they transport?
- Capillaries connect arteries and veins
- They carry both oxygenated and deoxygenated blood
Are the walls of arteries thick + why?
Arteries have thicker walls and blood flows through them with higher pressure
Are the walls of veins thick + why?
Veins have thinner walls and blood flows through them with low pressure
Are the walls of capillaries thick + why?
Capillaries have walls only one cell thick for diffusion
Arteries, veins, capillaries- valves?
Arteries- no valves
Veins- Have valves
Capillaries- no valves
Speed of blood in arteries and veins
Arteries- blood speed fast
Veins- blood speed slow
Tricuspid valve- location + allows blood to flow from
location: right atrioventricular septum
allows blood to flow from: right atrium to right ventricle
Bicuspid valve/mitral valve- location + allows blood to flow from
location: left atrioventricular septum
allows blood to flow from left atrium to left ventricle
Pulmonary valve- location + allows blood to flow from
location: at the origin of the pulmonary artery in the right ventricle
allows blood to flow from right ventricle into the pulmonary artery
Systemic valves/Aortic valves- location + allows blood to flow from
location: at the origin of the systemic aorta
allows blood to flow from the left ventricle into the systemic aorta
Duration of one cardiac cycle
0.8 second
Contraction of heart chambers
Systole
Relaxation of heart chambers
Diastole
Atrial systole
- Duration- 0.1 sec
- Deoxygenated blood (low pressure) enters right atrium
- Oxygenated blood enters left atrium
- Contraction of atria
- Blood flows into ventricles
- Atria act as a pump to collect and force blood into the ventricles
Atrial diastole
The atrium relapses
Ventricular systole
- Duration- 0.3 sec
- Ventricles contract
- Atrioventricular valves close (causing LUB sound)
- Ventricular pressure rises and exceeds blood pressure in the aorta and the pulmonary artery
- Aortic and pulmonary valves open
- Blood drained out from the ventricles into the vessels
- At the end of ventricular systole, ventricular diastole begins
Ventricular diastole
- Pressure falls in the ventricles
- High pressure in the aorta and pulmonary artery forces a small amount of blood towards the ventricles, thus closing the semi-lunar valves (causing DUP sound)
- Atria and ventricles continue joint diastole (Cardiac diastole - 0.4 second)
How is systolic pressure measured by a sphygmomanometer?
- Air is pumped into the cuff until the pressure is sufficient to stop the flow of blood in the branchial artery. No sound is heard.
- The doctor then slowly releases air until he hears the first pulse.
- Pressure of air in the cuff is slightly lesser than the pressure of the blood in the branchial artery. (>120 mm Hg)
- The reading that is noted is the systolic pressure
How is diastolic pressure measured by a sphygmomanometer?
- The doctor releases a little more air after measuring the systolic pressure, stopping at the point when no more sound is heard (<80 mm Hg)
- The reading is noted
- This is the diastolic pressure
Heart rate
Heart rate is the rate at which the cardiac muscles contract and relax rhythmically. Thus, the heart rate of a healthy adult at rest is normally 70-75 per minute.
Pulse
Pulse is a wave felt along the wall of an artery due to the contraction of the left venticle. Pulse is the heart rate i.e. the number of times the heart beats per minute.
Normal pulse rate is 60-100 beats per minute
What is cardiac output?
- Measure of blood volume ejected from the heart over a given time
- It maintians blood flow throughout the body
- Determined by multiplying heart rate by stoke volume (CO= SV * HR)
- 5.25 L/min
What is heart rate?
formula + value
Heart rate: Number of beats/ min
75 beats/min
Stroke volume
Definition + value
Amount of blood ejected from the ventricles during one heartbeat
70 mL/beat
ECG
full form + definition
ECG (Electrocardiogram) is a graphical representation of the electrical activities of the heart during a cardiac cycle
P-Wave
Depolarisation of atria in response to sinoatrial (SA) node triggering
little bump at the start
PR Interval
Delay of AV (atrioventricular) node to allow filling of ventricles
little flat thing after P wave
QRS complex
Depolarization of ventricles, triggers main pumping contractions
tall mountain part
ST Segment
Beginning of ventricle repolarization, should be flat
flat part after QRS complex
T-Wave
Ventricular repolarization
little bump at the end
Composition of blood
- Plasma- 55%
- Formed elements- 45%
Composition of plasma
- Proteins- 7% (Albumins, Globulins, Fibrinogen, Prothrombin- blood coagulation)
- Water- 91%
- Other solutes- 2% ( Ions, nutrients, waste products, gases, regulatory substances)
Composition of formed elements of blood
- Platelets <1%
- Leukocytes (WBCs) <1%
- Erythrocytes (RBCs) >99%
Leukocytes: classification
Agranulocytes
Lymphocytes- 20-25%
Monocytes- 3-8%
Granulocytes
Neutrophils- 60-70%
Eosinophils- 2-4%
Basophils- 0.5-1%
Blood coagulation: process
- At injury site, the tissues release platelets and clotting factor prothrombin activator (Thrombokinase) and calcium ions
- Prothrombin activator converts prothrombin to thrombin
- Thrombin in turn converts fibrinogen into fibrin
- Fibrins form mesh like structure in which red blood cells get trapped
- Clot is formed and bleeding stops
Hypertension
- Disorder of the circulatory system
- High blood pressure above the normal 120/80 mm/Hg
Coronary Artery Disease
Mention coronary heart disease
- Disorder of the circulatory system
- The coronary arteries become narrow, reducing the blood flow to the heart
- This results in Coronary Heart Disease, a condition in which the heart muscle is damaged because of an inadequate supply of blood due to obstruction of its blood supply.
Angina pectoris
Symptoms, definition
Definition: Attacks of choking or throttling pain across the upper part of the chest due to reduction in blood flow through the coronary arteries which supply heart muscles is known as angina pectoris.
Symptoms
* Chest pain (angina)
* Fatigue
* Shortness of breath
* Cold sweats
Cardiac arrest/Heart failure
Cause and symptoms
Heart is not pumping blood effectively enough to meet the needs of the body
Cause: Usually triggered by a problem with the heart’s electrical impulses
Symptoms:
* Loss of consciousness
* No pulse or breathing
Myogenic heart
- In myogenic heart, the cardiac movement is initiated rhythmically by cardiac muscles themselves.
- Acetylcholine inhibits the heart beat.
- This type of heart is found in molluscs and vertebrates
Who was the pacemaker first used by?
Chardack
What is a pacemaker?
A tiny computerised electrical device that is implanted in the patient’s body to regulate heart beat.
Electrodes from it are usually connected to the right ventricle.
Neurogenic heart
- Cardiac movement is initiated by nerves arising from the brain
- Heart of all invertebrates except molluscs
