6.2 The Blood Flashcards
What does blood transfer
- oxygen
- nutrients
- antibodies
- hormones
- heat
- CO2
• UREA
Erythrocytes
Red Blood Cells (O2 in the hemoglobin)
Leucocytes
White Blood Cells
• phagocytes- eat up pathogens and dead cells
• immune response (B-cells and T-cells)
What does blood consist of
- plasma
- erythrocytes
- leucocytes
- platelets
Right side of the heart
Deoxygenated Blood- blood from the body to the heart
- Superior Vena Cava and Pulmonary Artery
- Inferior Vena Cava
• Tricuspid Valve and pulmonary valve
Left side of the heart
Oxygenated blood from the lungs to the body
- Pulmonary veins
- Aorta
•Bicuspid Valve and Aortic valve
Arteries
carry high-pressure blood away from the heart
Capillaries
- very small
- blood moves through them slowly and under low pressure
- allows for the exchange of substances to tissues
- between veins and arteries
Veins
carry low-pressure blood to the hear
* Valves prevent backflow
Simple structure of arteries
- relatively small lumen and thick walls: to maintain a high blood pressure
More complex structure of arteries (muscles and fibers)
- thick muscular wall and fibrous outer layer help the artery withstand pressure
- muscles contract to decrease the size of the lumen which helps increase blood pressure
- elastic fibers stretch which expands the lumen with each pulse
- after each pulse the fibers recoil which decreases the size of the lumen to maintain a high pressure
Endothelium
cells that line the interior surface of blood vessels and lymphatic vessels
The structure of capillaries
- smallest type of blood vessel
- exchange substances to and from the blood
- Into the blood: waste such as CO2, nitrogenous waste, and UREA
- Out of blood: nutrients and O2
How do capillaries allow for a short diffusion pathway?
they can fit into small spaces
(no valves)
- their walls are 1 cell thick
- blood travels slowly at a low pressure allowing for exchange to take place
- a large number of capillaries and a small lumen (larger surface area allows for a faster rate of exchange)
- pores between cells (also allow phagocytes to squeeze out)
Basement membrane
Thin membrane of the outside of capillary vessels
- permeable to many substances
The structure of veins
- large lumen
- relatively thin walls
which allow for a low blood pressure
• walls contain less muscle that in arteries and are less elastic
VALVES are required to prevent the backflow of blood due to the low blood pressure
Explain how arteries have been adapted to perform a specific function
- thick walls and narrow lumen allow for high blood pressure
- large amounts of muscles and elastin fibers
- smooth muscle contractions propel blood forwards
- thick collagen and fibers to prevent bursting
- valves at the exit of the heart prevent backflow
Explain how capillaries have been adapted to perform a specific function
- smallest blood vessel
- small lumen and thin walls allow for a low pressure
- large number and each has a small lumen which increases the surface area allowing for short diffusion pathways
- includes pores which allow white blood cells to move to tissue
Explain how veins have been adapted to perform a specific function
- thin walls and a relatively wider lumen (low pressure)
- valves that prevent backflow
- thin which allows them to be pressed by muscle to pump
- decrease resistance to flow (lower pressure)
Pneuma
The ancient Greek word for Breath
William Harvey
discovered the circulation of blood with the heart acting as a pump
- blood flows through blood vessels in one direction (which doesn’t change) with valves to prevent backflow
- blood isn’t consumed by the boy but flows back to the heart
- the heart pumps blood into arteries and it comes back via veins
- predicted that there be small vessels between veins and arteries by there were no microscopes yet
Double Circulation
blood passes through the heart twice on one circuit of blood
- deoxygenated blood returns to the heart via the right atrium-right ventricle-lungs
- oxygenated blood enters the left atrium-left ventricle-body
Myogenic
When a cell contracts by itself (no need for nerve impulses)
- the beating of the heart is due to myogenic contraction
Myocyte
muscle cell that contracts by itself
Sinoatrial Node
the region of myocytes that control the rate of the heartbeat
- wave of excitations are sent from the SA node which causes the atria to contract
- excitation is conducted to the atrioventricular node
- passes through nerves to the muscles of the ventricles which causes them to contract
The heart rate can be increased or decreased by impulses brought to the heart through two nerves from……
the medulla of the brain
Autonomic nervous system
Responds to changes in body conditions
- can control the heart rate
When you exercise more…. is present in the blood
CO2
When there is too much CO2 present in the blood
chemoreceptors in the medulla oblongata send a nerve signal to the SA node which speeds up the heart rate
When CO2 levels fall the …… reduces heart rate
Vagus Nerve
Sympathetic nervous system
Spinal Nerve
- Part of the autonomic nervous system
Part of the fight or flight reaction, causes muscles to contract and heart rate to increase.
INCREASES HEART RATE
Parasympathetic Nervous System
Vagus Nerver
- Part of the autonomic nervous systen
controls functions of the body at rest
