Circulatory system Flashcards
What type of circulatory system is our circulatory system
double loop circulatory system
what is the left side of the loop
pulmonary loop
carries deoxygenated blood from the heart to the lungs and back to the heart
what is the right side of the loop
systemic loop
carries oxygenated blood from the heart to the body and back to the heart
How does the heart beat happen
- made of cardiac muscles
- electrical impulses from brain cause first atria and then ventricles to contract and relax
what are the phases of a heartbeat
phase 1: atrial systole (atria’s are contracting)
phase 2: ventricular systole (ventricles are contracting)
phase 3: atrial and ventricular diastole (heart relaxes)
what is phase 1 of a heartbeat
- atrial systole
- when the sino-atrial (SA) node causes the atria to contract
what is phase 2 of a heartbeat
- ventricular systole
- when the atrio-ventricular (AV) node causes ventriculus to contract
what is phase 3 of a heartbeat
- diastole
- when the chambers are relaxing
what is blood pressure
the pressure exerted on the wall of the arteries
- two types
what are the two types of blood pressure
- systolic pressure
- diastolic pressure
what is systolic pressure
the pressure that the blood exerts on the aorta when blood leaves the heart during systole
what is diastolic pressure
the pressure that the blood exerts on the aorta when no blood leaves the heart during diastole
how does the heart work
step 1: heartbeat begins when heart muscles relaxes and blood flows into the atria. process is called diastole
step 2: atria then contract and valves open to allow blood into the ventricles. called atrial systole
step 3: valves close to stop blood flowing backwards. ventricles contract forcing blood to leave the heart. process called ventricular systole. at the same time atria are relaxing and filling up with blood
what does the electrocardiograph do
records electrical activity of heart to monitor heart function
what are the P to Q wave
SA (sino atrial) impulse or atrial depolarization (loses electrical charge)
- atrial systole
what is the Q to R to S wave
AV (atrio ventricular) impulse or ventricular depolarization (loses electrical charge)
- ventricular systole
what is the S to T wave
ventricular repolarization (regains electrical charge)
- diastole
cellular respiration equation
glucose + 6 oxygen = 6 carbon dioxide + 6 water + ATP
What does the circulatory system do
circulates blood and lymph through the body
what does the circulatory system consist of
- heart
- blood vessels
- blood
- lymph
- lymphatic vessels and glands
what are the functions of the circulatory system
- 3 function
1. transporting substances around the body
2. controlling body temp
3. protecting body
how does the circulatory system protect the body
- blood contains cells and anti bodies that fight infection and clotting agents to stop bleeding
what is blood
the liquid circulating in the arteries and veins as a mean to transport substances around
what does blood transport
- oxygen (from lungs to the heart to body tissues)
- carbon dioxide (from tissue to heart to lungs to be exhaled)
- hormones (from one organ to another)
- nutrients & minerals (from small intestines to tissues)
- water (from digestive system to all cells)
- waste products )from all cells to kidneys)
What is blood made up of
- plasma
- formed elements of RBC, WBC and platelets
where are RBC, WBC and platelets made
in the bone marrow
What is plasma made of
- 90% water
- inorganic salts
- glucose
- antibodies
- urea and other waste products
- plasma proteins (e.g. fibrin - to clot blood)
How can plasma be separated from the other components of blood
by using a centrifuge
Red blood cells info
- called erythrocytes
- lack nucleus
- disk shaped
- life span of about 120 days
- contain hemoglobin that bonds with oxygen to form oxyhaemoglobin
- transports oxygen from lungs to tissue
- transports carbon dioxide from tissue to lungs
- each RBC contains millions of Hb molecules
White blood cells info
- called leucocytes
- bigger than RBC’s with large nuclei
- body’s defence system
- some are surrounded and consume (phagocytose) harmful microbes and foreign particles
- some produce antibodies to fight infection
Platelets info
- cell fragments
- lack nucleus
- life span about 10 days
- together with coagulating factors or clotting factors they help form blood clots
what happens when platelets form a clot
they grow into irregular shapes and stick together to form a plug over the wound
what are the 3 types of blood vessels
-artery
- vein
- capillary
what does the artery do
carries blood away from the heart
what does the vein do
carries blood back into the heart
what does the capillary do
carries blood to and from body cells
what is the structure of arteries
- thick outer wall
- thick inner layer of muscle and elastic fibers
- lumen is narrow
what is the lumen
central tube in the arteries and veins
what is the structure of veins
- thin outer wall
- thin inner wall of muscle and elastic fibers
- lumen is wide
what is the structure of capillaries
wall is only 1 cell thick
what is the blood pressure in the arteries
speed: high
Width: medium
Pressure: high
what is the blood pressure in the veins
Speed: low
Width: wide
Pressure: low
what is the blood pressure in the capillaries
Speed: medium
Width: medium
Pressure: medium
how does blood flow in the veins happen
- have valves to prevent backflow
- valve open: allow blood to flow in right direction
- valve close: blood starts to flow in wrong direction
what is the heart protected by
- sternum (breastbone)
- ribs
- spine
what are the two sides of the heart separated by
a muscular septum
what is the inside surface of the heart lined with
- endocardium tissue which provides a smooth surface to minimize friction
- myocardium tissue which allows the heart to contract
what is coronary circulation
- circulation of blood to the heart
what does coronary circulation consist of
a right coronary artery and a left coronary artery which has two major branches: circumflex artery and the descending artery
what can a disease or blockage of the coronary arteries cause
- angina
- heart attack
what are the nerves that control the heart beat
- sinoatrial node
- atrioventricular node
- bundle of His
- purkinje fibres
what is the sinoatrial node
- a cluster of heart muscle cells influenced by medulla oblongata (brain stem)
- found near opening of superior vena cava
- Initiates cardiac cycle (systole/diastole)
- Sets basic rhythm for the heart
what is the Atrioventricular Node
- Found at the base of the right atrium
- Briefly delays impulse so that atrial contraction can finish before ventricular contraction
what is the Bundle of His
- also known as atrioventricular bundle or A-V bundle
- spreads impulse over ventricles causing ventricular contractions
what are Purkinje fibres
Specialized conduction fibres found throughout the heart
cardiac cycle
Pressure changes within the heart’s chambers generated by contraction and relaxation are responsible for blood movement and cause the heart valves to open and close, preventing the backflow of blood
What does the lub sound do
AV valves close; semilunar open (blood moves away from ventricles)- soft sound
what does the dub sound do
semilunar close; AV valves open (blood pours into the ventricles) - hard sound
how do doctors hear the heart beat
by using the stethoscope
what is a heart murmur
swish noise when valves aren’t completely closing and blood is moving backwards
what is pulse
number of heart beats per unit time
Systole in ECG
- P wave
- QRS complex
Diastole in ECG
T wave
what does depolarization lead to
contraction
what does repolarization lead to
relaxation
what is the P wave
contraction (depolarization) of atria in response to SA node triggering
what is the PR interval
delay of AV node to allow filling of ventricles
what is the QRS complex
contraction (depolarization) of ventricles, triggers main pumping contractions
What is the ST segment
beginning of ventricle relaxation (replorization)
should be flat
what is the T wave
ventricular relaxation (repolarization)
Trace the path of the blood as it leaves the inferior vena cava
- Enters the right atrium is when the SA node triggers allowing atrial systole to happen; when the atria to contract opening the tricuspid valve allowing blood to flow into the right ventricle
- Then the AV delays for a bit to allow the blood to fill the ventricle and then allows ventricular systole which pushes the blood past the pulmonary semilunar valve into the pulmonary arteries which then carry the deoxygenated blood to the lungs
- The pulmonary veins carry oxygenated blood from the lungs to the heart which enter the left atrium
- Once the blood is in the left atrium the SA node then triggers which makes the atria contract opening the bicuspid valve allowing blood to flow into left ventricle
- Then the AV valve delays for a bit to allow the blood to fill the ventricle and then triggers allowing ventricular systole which pushes the blood past the aortic semilunar valve through the aorta to the rest of body. At the same time atrial systole is happening in our right atrium
