Chapter 8 ~ Transport In Animals Flashcards
Why are specialise transport systems needed
For high metabolic demand
To maintain steep concentration gradient
To overcome a low surface area to volume ratio
To allow diffusion across a large distance
Transport a hormones and enzymes
Transport waste products
What is an open circulatory system?
It is not enclosed in blood vessels
The heart pumps the blood around the body under pressure and blood returns directly to the heart
What is a closed circulatory system?
Blood is enclosed in blood vessels
The heart pumps blood around the body and the body returns it to the heart
Substances will move between the bloodstream and and tissues at the capillary and arteries take blood away from the heart and organs veins take blood from the tissue back to the heart
What is a single closed circulatory system
Blood flows through the heart and is pumped out to travel all around the body before returning to the heart
ONCE
What is the double circulatory system?
Blood travels in two loops
Blood pumped from the heart lungs pick up oxygen and unload CO2
Blood flows through the heart and is pumped out to travel all around the body
Blood essentially travels twice
What is elastic fibre?
Composed of elastin which can stretch and recoil providing flexibility
What is smooth muscle?
Contracts or relaxes, changing the size of the lumen
What is collagen?
Provides a structural support to maintain the shape and volume of the vessel
What are arteries?
Arteries carry oxygenated blood away from ❤️
What are the exceptions of carrying oxygenated blood for arteries?
Pulmonary artery, which carries the deoxygenated blood from the heart to the lungs, and during pregnancy that umbilical artery carries deoxygenated blood from the fetus to the placenta
Does the arteries carry blood under high pressure or low pressure
High pressure
What is a structure of the artery?
Is made of elastin fibre, which allows the walls to expand, allowing continuous flow of blood
It has smooth muscle, which allows easy blood flow
It is made up of collagen
Thick muscular wall containing lots of elastic tissue to withstand the force of high pressure of blood
Inner lining endothelium which is folded, allowing the artery to expand elastic boil recoil .
Small lumen to withstand high pressure
Explain vasconstriction
When the smooth muscle in the arteriole contract, it constricts the vessels, and prevents blood flowing into the capillary bed
Explain vasodilation
When the smooth muscle in the wall of an arteriole relaxes blood flows through into the capillary bed
What is the function of the arteriole
It links the artery to the capillary and vasoconstriction and vastdilation
What is the structure of the capillary?
. Thin endothelium and narrow lumen for short diffusion
Many capillaries, which are highly branched forming a large network for a large surface area
Single endothelial cell thick, allowing a short layer of diffusion
Small holes enabling exchange of substance
Blood entering the capillary is
Blood leaving the capillary is
Oxygenated
Deoxygenated
Function of the vein
Carry deoxygenated blood away from cells towards the heart
What what are the exceptions of the veins carrying the deoxygenated blood?
The pulmonary vein and umbilical vein carry oxygenated blood
Structure of the veins
Lots of collagen and little elastic fibre
Large lumen and thinner walls as blood is flowing LOL pressure
Valves which prevent the backflow of blood
What does venules do
Link capillaries with veins
Structure of venules
Thin walls with smooth muscle
Functionof valve
Prevent backflow
What does blood consist of?
Plasma, erythrocytes, platelets, leuocytes
What is tissue fluid?
It is fluids surrounding tissues formed from blood plasma
What is hydrostatic pressure?
Pressure exerted by fluid
What is oncotic pressure?
Tendency of water to move into blood via osmosis
Explain the process of tissue fluid formation
Arterial end:
There is a high hydrostatic pressure which is greater than oncotic pressure.
This forces fluid and dissolved substances out of the capillary forming tissue fluid
Venous end:
Water potential is lower inside capillary compared to tissue fluid.
This means there is a high oncotic pressure which is greater than hydrostatic pressure.
This forces water out