Module 3 Section 2 - Animal Circulatory System Flashcards
Pyper
Two circulatory systems in mammals
- Pulmonary system
- Systemic system
Describe why multicellular organisms need a transport system. (4)
- Multicellular organisms have a low surface area to volume ratio
- High level of metabolic rate/activity -> lots of respiration occurs
- Hormones and antibodies need to move around the body
- Maintains a steep concentration gradient for diffusion
Fish only have one circuit in their circulatory system. Suggest why.
They don’t need to support their body in water (more support is needed on land) and less thermoregulation is required n water
benefit of a double circulatory system
Blood gets around the body and to the cells that need it faster
Compare and explain the pressure differences in the two circulatory systems in mammals.
Lower pressure -> blood needs (a bit) more time for gas exchange to occur
Systemic system has a higher pressure -> gets to cells much faster
closed system
blood is always enclosed in a blood vessel
open system
transport medium (don’t say blood) isn’t always enclosed in a blood vessel as it sometimes flows freely inside the body cavity
What does an insect transport medium carry?
Nutrients other than oxygen
capillaries function
To exchange substances with the tissue fluid that surrounds groups of cells
venules function
To control blood flow between capillaries and veins
There are five types of blood vessels between the lungs and heart. T/F and why?
False - there’s only two blood vessels connecting the lungs and heart i.e. the arteries and veins
muscle tissue function [2 marks]
Muscle tissue contracts (1) and expands to control the volume of blood that flows to tissues (1)
elastic fibres function (2)
Stretch at high pressures and recoil at low pressures (1/2) to maintain blood pressure (1)
artery endothelium adaptation with 2 explanations
endothelium layer is folded to allow the artery to stretch/expand without breaking apart and maintains blood pressure
Movement of blood flow through veins is helped by the ____ of ___ ___.
contraction (of) body muscles
capillary adaptations and explanations
Permeable walls for nutrient exchange
Narrow -> large SA:V
Explain why it’s an advantage for capillaries to be slightly smaller than erythrocytes.
Erythrocytes have to squish aganist the capillary walls, decreasing the diffusion pathway -> more efficient gas exchange
Erythrocytes have a biconcave disc shape. Explain how this is advantageous for nutrient exchange. [2]
Erythrocytes are flexible (1) so can fit through (the smaller) capillaries
Why is it that veins carry blood at low pressures? What exactly causes this drop in pressure compared to in arteries?
Red blood cells are forced through blood vessels, so the blood pressure decreases further on (i.e. by the time the blood has gone to cells, the pressure has decreased as a large distance has been travelled from the heart)
For understanding ig
List the places blood flows through/to as it goes through the circulatory system, starting with deoxygenated blood at the heart.
Heart -> arteries -> lungs -> veins -> heart -> arteries -> arterioles -> capillaries (next to tissue fluid + cells) -> venules -> veins -> heart
where italics = deoxygenated blood
How can you distinguish arteries from veins in a photograph? Explain why.
Arteries tend to be circular due to the thicker muscle tissue that keeps them firm (like plant cell walls).
Veins therefore tend to be less uniform.
Arterioles contract to…
Allow less blood to flow to capillaries (ig a slower blood flow allows more time for diffusion of substances)
What do venules contain?
Endothelium tissue and may contain smooth muscle (NO elastic tissue for spec)
