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
Function of the middle layer of an artery
Allows the artery to stretch when blood under high pressure is pumped into it
The inner space of a blood vessel through which blood flows
lumen
Describe a capillary
- Microscopically small
- walls made of a single layer of endothelium
- Lumen only allows red blood corpuscles to move in single file
What happens in the capillaries?
- Exchange of substances
- Gases, nutrients and waste products pass through the endothelium
- Blood flow is quite slow allowing diffusion to take place
Structure of veins compared to arteries
- Same three layers as an artery
- outer two layers are thinner
- Lumen larger
- Lumen irregular in shape
- blood pressure lower
How blood is able to flow in veins
- Contraction of skeletal muscles close to the veins
- squishes the blood
- valves ensure blood flows in a particular direction
Blood tissue composition
- Red blood corpuscles
- White blood cells
- Blood platelets
- Blood plasma
Functions of blood plasma
- Transports nutrients
- Transports waste products
- regulates body temperature
- transports hormones
- Plasma proteins ensure that blood can clot to help healing
Structure of red blood corpuscles
- Small, disc shaped cells
- soft and pliable and can be pressed flat
- they are bi concave (indented on both sides)
- have no nuclei
- contain haemoglobin, an iron containing protein
Functions of red blood corpuscles
- Transport oxygen as oxyhemoglobin
- from lungs to the tissues
- Transport carbon dioxide as carbaminohaemoglobin
- from the tissues to the lungs
How does the blood change with altitude?
- As altitude increased, the air pressure decreases
- As air pressure decreases, the less oxygen is available when we breath
- The body produces more red blood corpuscles if you stay at high altitude
- This results in more effective transport of the limited oxygen breathed in
What does acclimatization to altitude mean?
- A person needing to exercise at high altitudes e.g. an athlete
- Needs to arrive a few days before the event if they normally live at sea level.
- This gives their body time to make extra red blood corpuscles
- Otherwise the athlete will tire very quickly
- because of their tissues not getting enough oxygen.
The structure of white blood cells
- Larger then red blood corpuscles
- not a fixed shape
- transparent and almost colorless
- have a nucleus
- can move through walls of capillaries and between cells
Two main types of white blood cells
- Phagocytes
- Lymphocytes
Functions of white blood cells
Our active immune system:
- Phagocytes move around and engulf bacteria and foreign substances
- Lymphocytes produce antibodies that destroy bacteria and viruses
Blood platelets
- Flat discs that have no nucleus
- Help with blood clotting in damaged blood vessels
Pulmonary circulatory system
- Blood flows from the heart to the lungs and back
- Leaves the right ventricle and
- enters the left atrium
Systemic circulatory system
- Blood flow from the heart to the body tissues and back to the heart
- Blood leaves the left ventricle and
- enters the right atrium
An operation where an unhealthy heart is removed and replaced with a healthy heart from a brain dead or dead donor.
Heart transplant
A surgical procedure providing alternative route for blood flow to the cardiac muscle.
Heart bypass
A procedure that is carried out to stretch a narrowed artery and remove a blockage.
Angioplasty
A blood clot which forms in one part of the body, breaks off and is transported to a coronary artery where it causes a blockage.
Coronary embolism
Blood clot formation in a coronary artery.
Coronary thrombosis
Condition charatcterised by fat deposits (cholesterol) on the inside of blood vessels resulting from narrowed arteries.
Atherosclerosis
When the blood supply to the cardiac muscle is interupted and leads to death of a part of the cardiac muscle tissue.
Heart attack
The loss of brain function due to a disturbance in the blood supply to the brain.
A stroke
High blood pressure
Hypertension
Low blood pressure
Hypotension
The unit in which blood pressure values are measured.
mmHg / millimetre mercury
Apparatus used to measure blood pressure.
Sphygmomanometer
(“Sphyg - mo - manometer”)
The force that is exerted by circulating blood on the walls of the blood vessels.
Blood pressure
Hereditary cardiovascular diseases
Congenital diseases
Diseases of the heart and blood vessels
Cardiovascular diseases
A swelling which develops when tissue fluid is not drained efficiently.
Oedema
Small bean shaped structures distributed close to the lymphatic vessels.
Lymph nodes
The blood vessel into which the right lymphatic duct opens.
right subclavian vein
The main lymphatic vessel into which the lymphatic vessels fromm the right side of the chest, right arm and right side of the head and neck open.
right lymphatic duct
The blood vessel into which the thoracic duct opens
left subclavian vein
The main lymphatic vessel into which the lymphatic vessels from the lower limbs, intestines, left side of the chest, left arm and left side of the head and neck open.
thoracic duct
System of small, blind ending lymphatic vessels that originates and branches between the cells and tissues.
lymph capilaries
The fluid that was drained between the cells of the tissues and transported back to the blood stream.
lymph
The fluid that was forced through the capillaries and surrounds the cells of the tissues.
Tissue fluid
The liquid part of the blood which is forced through the walls of the blood capilaries as a result of blood pressure.
Blood plasma
Number of heartbeats per minute
pulse rate
Hormones responsible for accelerating heartbeat
adrenaline and thyroxine
Nerve fibres that conduct impulses that slow the human heartbeat down to normal.
parasympathetic nerve fibres
Nerve fibres that conduct impulses that accelerate the human heartbeat
sympathetic nerve fibres
The part of the human nervous system that controls the heartbeat
- autonomic nervous system
- (Medulla oblongata)
Conducting tissue in the human heart that ensures that te ventricles contract simultaneously from their lower ends.
Purkinje fibres
Conducting tissue in the human heart through which impulses pass to the Purkinje fibres.
Bundle of His
Conducting tissue in the human heart that conducts impulses to the bundle of His.
AV/atrio-ventricular node
Conducting tissue in the human heart known as the pacemaker.
SA/sino-atrial node
A network of fibres that branches from the Bundle of Hs, at the apex of the heart.
Purkinje fibres
Special muscle tissue that extends throughout the septum between the two ventricles.
Bundle of His
A group of specialise muscle cells at te lower end of the septum between the right and left atrium.
AV/atrio-ventricular node
A group of specialised muscle cells in the wall of the right atrium.
SA/sino-atrial node
The instrument used to liosten to the heartbeat.
Stethoscope
Blood vessels where exchange of substances to and from the cells occur.
Blood capillaries
Left atrium
Bicuspid valve
(Mitral valve)
