VASCULAR SYSTEM Flashcards
BLOOD
If spun for a few minutes in a high-speed centrifuge, it separates into two layers:
1) 45% cells
2) 55% plasma
PLASMA
Liquid part of your blood
PLASMA CONTAINS:
(1) water: helps carry nutrients and waste around the body - 92%
(2) proteins: help with things like blood clotting and keeping the right amount of fluid in your body
(3) electrolytes: like sodium and potassium, which helps with muscle function
(4) nutrients and waste: glucose (sugar), hormones, and waste products like carbon dioxide.
CELLS INVOLVED IN BLOOD ARE:
(1) red blood cells- these carry oxygen from your lungs to the rest of your body and bring back carbon dioxide to be exhaled. They have a special protein called haemoglobin
(2) white blood cells- part of you immune system. Helps fight off infection
(3) platelets- tiny cells help your blood clot when you get a cut
FUNCTION OF BLOOD
(1) Transport nutrients- blood carries oxygen (glucose, lipids, amino acids , hormones) from the lungs to the body and brings co2 back to lungs to be exhaled
(2) regulation- help keep you body temperature stable
(3) protection- contains white blood cells that fight infection, platelets that help your body heal by stopping bleeding when you get hurt/cut.
ARTERY
Vessel wall - strong and elastic, thick muscular wall
Diameter - larger than arterioles but smaller than veins (4mm)
Valves - no valves, because of high blood pressure
Pressure - high pressure to pump blood away from the heart
Blood - oxygenated blood except from pulmonary
Blood flow - one direction away from the heart
Function - carry oxygen rich blood away from heart to the rest of the body. Distribute nutrients
ARTERIOLES
Vessel wall - thinner than arteries, undergo pressure but regulate blood flow
Diameter - smaller than artery (30 micrometer)
Valves - no valves
Pressure - high but lower than arteries
Blood - oxygenated blood
Blood flow - take blood to capillaries
Function - regulate blood flow and pressure by constricting and dilating. This also helps control the distribution of blood by adjusting diameter. At the junction of the capillary is a pre-capillary sphincter that can vasodilate
CAPILLARIES
Vessel wall - very thin wall to allow gaseous exchange (one cell thick)
Diameter - very small (5-10 micro meters)
Valves - no valves
Pressure - low pressure
Blood - starts with oxygenated and ends with deoxygenated for GE
Blood flow - slow blood flow for maximised diffusion
Function - take waste products and release nutrients waste (CO2)
VENULES
Vessel wall - thin wall with some smooth muscle
Diameter - larger than capillaries but larger than veins
Valves - some venules have valves especially in lower part of body to allow blood back to the heart
Pressure - relatively low compared to artery
Blood - deoxygenated blood
Blood flow - towards heart slow
Function - collect deoxygenated blood towards veins
VEINS
Vessel wall - thin walls made of thin layers less muscular than arteries
Diameter - larger than arteries
Valves - has valves
Pressure - low pressure
Blood - deoxygenated blood
Blood flow - back towards the heart
Function - carry deoxygenated blood back to the heart through superior and inferior vena cava
ORDER IN WHICH BLOOD FLOWS THROUGH THE VASCULAR SYSTEM IS :
1) heart
2) arteries
3) arterioles
4) capillaries
5) venules
6) veins
VASCULAR SHUNT
The action of the smooth muscle around the arterioles (vasodilation & vasoconstriction) and the action of pre-capillary sphincters will direct blood to where it is needed and restrict it where it it not needed
VASODILATION
Is when blood vessels get wider, allowing more blood to flow through them.
VASOCONSTRICTION
The process where blood vessels become narrower, reducing blood flow
PRE-CAPILLARY SPHINCTERS
A tiny muscle that controls blood flow into capillaries, which are the small blood vessels where oxygen and nutrients are exchanged
CARDIAC ARRHYTHMIA
When the heart beats in an irregular way, beating too fast, too slow or unevenly
It happens because the electrical signals that control the hearts rhythm are not working properly
Tachycardia
Beating too fast
BRADYCARDIA
Beating too slow
VASCULAR SHUNT MECHANISM
During rest, blood flow (80%) primarily goes to the brain, kidneys, liver, skin (even intestine) to carry out normal bodily functions such as digestion and removal of waste products
Exercise causes an increase demand for oxygen from the muscles, where 80% of blood flow is not redirected to the working muscles
The action of smooth muscle around arterioles and the action of pre-capillary sphincters will direct blood to where it is needed and restrict it where it is not needed
REDISTRIBUTION OF BLOOD IS IMPORTANT TO :
- increase the supply of oxygen to the working muscles
- remove waste products such as carbon dioxide and lactic acid from muscles
- ensure more blood goes to the skin during exercise to regulate body temperature (dissipate) and get rid of heat through radiation, evaporation and sweating
- direct more blood to the rest of the heart, since it is a muscle that require extra oxygen during exercise
VASOMOTOR CONTROL CENTER
Control of heart rate and breathing, chemoreceptors pick up chemical changes in the blood through an increase in carbonic acid (CO2 in blood) and lactic acid
Baroreceptors pick up changes in systolic blood pressure in the aorta and carotid artery
Send this information to the VASOMOTOR CONTROL CENTRE (VCC) in the medulla oblongata
Arterioles have a middle layer of muscle which is connected to the VCC which become stimulated via the sympathetic nerve
