Circulatory systems Flashcards
Main components of blood circulatory systems
- Heart
- Blood vessels
- blood
Open circulatory systems
- Blood flows freely over tissues,
- Through an open cavity called a haemocoel
- Blood flows slowly at low pressure
- No control over the blood’s distribution
- Found in some small animals like arthropods
Closed circulatory systems
- Blood flows all the time in a system of vessels – arteries, veins and capillaries
- Leaves heart and arteries branch to eventually form capillaries
- Capillaries join up again to form veins that takes blood back to the heart.
- Found in all vertebrates including humans and all mammals
Double pump closed circulation
- The heart has four chambers
- That function as two separate pumps
- Systemic and pulmonary circulation
- Found in all mammals
Size and shape of the human heart
- About the size of your fist
- Hollow, pear shaped muscular organ
- Upper end wider than lower end that points down and to the left
Where the heart is located
- Found in the thoracic cavity
- Above your diaphragm between the lungs
- Protected by the sternum and ribs
- Large blood vessels enter and leave it at the top and keep it in position.
Pericardium
- A double walled membrane
- Enclosing the heart
How the heart is protected from friction
- Watery fluid
- Between the pericardium
- Prevents friction between heart and surrounding organs
How the heart itself gets blood
- Coronary blood vessels
- coronary arteries
- coronary veins
Muscular wall dividing heart into left and right side
Septum
Side of the heart with oxygenated blood
Left
Side of the heart with deoxygenated blood
Right
The four chambers of the heart
- Left atrium
- left ventricle
- Right atrium
- right ventricle
Describe the upper chambers of the heart
- Atria
- Receiving chambers
- Thinner muscular walls
Describe the lower chambers of the heart
- Ventricles
- Pumping chambers
- Thicker muscular walls
Endocardium
- Inside lining of the heart
- Thin membrane of squamous epithelium
Describe where the right hand side of the heart would be as you look at a picture of it
On the left of the picture.
Veins that open into the right atrium
- Superior vena cava
- Inferior vena cava
Valve separating the right atrium from the right ventricle
- tricuspid valve
- Three valve flaps
bicuspid valve
Valve separating the left atrium from the left ventricle
Blood in the superior vena cava
- Deoxygenated
- From the head and arms to the right atrium
Blood in the inferior vena cava
- Deoxygenated
- From the lower limbs and abdomen
Blood in the pulmonary arteries
- Deoxygenated
- From the right ventricle to the lungs
Valve between the right ventricles and the pulmonary artery
Semilunar pulmonary valve
The left atrium
- Four pulmonary veins enter the left atrium
- Bringing oxygenated blood
The bicuspid valve
- The valve between the left atrium and the left ventricle
- Consists of two valve flaps
Blood in the left ventricle
- Oxygenated
- Is pumped all over the body
- Leaves via the aorta
Blood vessels that transport blood away for the heart
Arteries
Chordae tendineae
- Inelastic tendons
- Connect the inner walls of the heart to the valves between atria and ventricles
How blood vessel valves work
- Small flaps of tissue
- They flatten against the sides of the structure when blood flows in correct direction
- When the blood flows in opposite direction the blood pushes the valve flaps up
- This closes the opening through which blood can flow
Semilunar valves
- At the base of the aorta and the pulmonary artery
- Where blood leaves the heart
- They look like half moon membrane sacks
- Point away from the ventricles in the direction blood should flow
The need for a circulatory system
- Animals tissues need oxygen and nutrients
- Waste products including carbon dioxide need to be removed
- More complex animals need a more efficient way of performing these functions
Three phases of the cardiac cycle
- Atrial systole
- Ventricular systole
- General diastole
Atrial systole
- 0,1 s
- Both atria filled with blood contract simultaneously
- Vein openings are squeezed closed
- Blood is pumped through atria-ventricular openings
Ventricular systole
- 0,3 s
- Ventricles contract simultaneously
- Tricuspid and bicuspid valves close
- Blood pumped into the main arteries leaving heart
General diastole
- 0,4s
- ventricles and atria relax
- blood is drawn from the veins into the atria
- blood is also able to flow from the atria into the ventricles
- the semilunar valves prevent blood from the arteries flowing back into the heart.
Main types of blood vessels
- Arteries
- Capillaries
- Veins
Types of arteries
- Arteries
- Arterioles
Types of veins
- Veins
- Venules
Artery structure
- outer fibrous layer of connective tissue
- middle layer of smooth muscle and elastic fibers
- inner endothelial layer of squamous epithelium