Download Notes Circulatory System

Unit 1 Biology
Transport Systems in Animals
Role of all transport systems:
 The transport of substances from the external environment to the body cells and vice
versa. eg. Oxygen and nutrients /Carbon dioxide and nitrogenous wastes such as urea.
Mammalian transport systems also need to:
 The transport of substances from one part of the body to another eg. Hormones made by
glands are transported to organs or muscles
 Distribute heat: Heat is generated as a product of cellular respiration in places throughout
the body and is used to maintain internal temperature
Different types of circulatory systems
All circulatory systems usually have the following:



a circulatory fluid of some sort
vessels in which circulatory fluid moves at some point
a mechanisms for moving the circulatory fluid
…..But they also differ:
Some organisms have an open circulatory system, in which the circulatory fluid is not totally
confined within vessels. The circulatory fluid simply flows over internal organs, delivering
requirements and picking up waste products. e.g. insects
Some organisms have no circulatory system
at all. e.g: amoeba
Mammals have a closed circulatory system. In a closed circulatory system the circulatory
fluid moves entirely within closed vessels. These vessels are the arteries, veins and
capillaries. The movement of this fluid is controlled with a pump (the heart). All vertebrates
and some invertebrates have a closed circulatory system.
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Unit 1 Biology
Component 1: Circulatory Fluid in Mammals: A Bloody Business



Materials are carried in a circulatory fluid called blood.
Materials are carried:
 From specialized body organs, where they are absorbed, to the cells of
the body, where they are used ....and
 From body cells to specialized organs for excretion.
Blood is composed of the following components that each perform a specific
role:
 plasma
 specialized blood cells,
 cell fragments and
 blood proteins
BLOOD
COMPONENT
Red blood cells
(erythrocyte)
Description
Mature rbc:
 Shape:


notable structural features:
55% plasma
45% cellular
componets
ROLE
carries most ____________
around the body
carries some ____________
_______________________

5- 6
million/mm3 of
blood

 colour:
 Size:
 live for:
White blood cells  Shape:
(leucocytes)
 numerous
Notable structural feature:
different

types
 each have a
slightly
 colour:
different role  size:
5000-10000 per
mm3 of blood
platelets


small cell “chips”
size:

_________________________
__________________________

destruction of damaged or
abnormal cells

production of antibodies

__________________________
__________________________
250000-400000
per mm3 of
blood
plasma



straw coloured fluid
suspends other blood components




55% of blood
2
begin a chain reaction that aids in
clotting.
transports __________,
__________ and ____________
suspends rbc and wbc
carries materials to stabilise pH
and osmotic pressure
carries blood clotting materials
and antibodies
Unit 1 Biology
Component 2: Blood vessels
Arteries
 fairly ___________
 _________lumen
 ___________ walled,
muscular, elastic
THIS STRUCTURE ENABLES
THIS TYPE OF VESSEL TO
WITHSTAND THE HIGH
PRESSURE OF THE BLOOD
FORCED INTO THIS VESSEL
 carry blood __________
from the heart
 carries blood under
__________________pressur
e
 carries ______________
blood (except the pulmonary
artery)
 Blood is forced along under
pressure when highly elastic
arteries recoil.
Veins
 __________than
comparative arteries with a
large lumen
 ______________ walls
than arteries
 carries blood directly
back to the heart (except
the hepatic portal vein)
 blood in veins is under
___________pressure
 carries
______________ blood
(except the pulmonary vein)
 relies on one way
valves and the contraction
of nearby skeletal muscles
to move blood along
Capillaries
 join arterioles to venules
 creates a
_____________ surface
area for supplying the
millions of body cells
 tiny vessels with
_________________walls
(one cell thick)
 diameter a little smaller
than that of a erythrocyte
 pressure falls from entry
of blood to exit of blood
Route of blood
From the heart, blood is carried around our body in different types of blood vessels. The
structure of each type suites it to its function.
Aorta  _________ Arteriole  ______________  Venule  __________ Vena cava

Oxygen poor blood leaves the right side of the heart via the pulmonary artery.
 Oxygen rich blood leaves the left side of the heart via the aorta. It then travels to some
part of the body via a smaller artery.
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Unit 1 Biology
For example:
Hepatic artery: leads to ____________________capillaries and hepatic vein leads away
mesenteric artery: leads to _________________ capillaries and hepatic portal vein leads
away towards the liver.
renal artery: leads to ____________________ capillaries and renal vein leads away
coronary artery leads to ___________________capillaries in the heart tissue and coronary
view lead away
carotid artery leads to ___________________ capillaries and the jugular vein leads away
subclavian artery leads to_________________capillaries and the subclavian vein leads away
Iliac artery leads to the ___________________capillaries and the iliac vein leads away
Pulmonary artery leads to _________________capillaries and the pulmonary vein leads away
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Unit 1 Biology
The Mammalian Heart




The heart is made up of _______________ muscle.
Size of _________________________
2 sides divided by wall of muscle = _____________
It is a double pump with _________ chambers;
THE
MAMMALIAN
HEART

2 Atria: (upper chambers): receive blood from vena
cava(R) and pulmonary vein(L) and contract to eject blood into
respective ventricles

2 Ventricles: (lower chambers): receive blood from atria and pump
blood into pulmonary artery(R) to deliver oxygen poor blood to the lungs
and into the aorta(L) to deliver oxygen rich blood to the rest of the body
Valves: Regulate direction of blood flow
Semi-lunar(SL) valves:
aortic value-at the beginning of aorta
 prevents backflow of blood from aorta into left ventricle.
pulmonary valve at the beginning of pulmonary artery
 prevents backflow of blood from aorta into left ventricle.
Atrio-ventricular(AV) valves: bicuspid(mitral): between left atrium and ventricle
 prevents backflow of blood from left ventricle into left
atrium
Tricuspid: between right atrium and ventricle
 prevents backflow of blood from right ventricle into right
atrium
Valves aim to prevent backflow of blood and thus keep blood flowing in one direction within
the heart
Heart Structure:
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Unit 1 Biology
Simple Plan of Circulation in mammals
Heart is a double pump; it pumps blood in 2 circuits simultaneously. The right side pumps
blood to the lungs and the left side pumps blood to the rest of the body.
Double circulation: blood will pass through heart twice in one complete circuit of the body.
one circuit- the pulmonary circuit carries blood to the lungs the other circuit-the systemic
circuit carries blood to other parts of the body
Component 3: The HEART
How the heart works:
Cardiac Cycle
Diastole (dilation)
 Atria and ventricles dilate (1)
 Semi lunar valves snap shut
 The Atrio-Ventricular(AV) valves open
 Blood enter atria and ventricles
Systole (contraction)
Brief contraction of atria (2)
Ventricles contract (3)
AV valves close (LUB) SL valves open
 Blood ejected from heart via arteries
Heart is relaxed…beginning diastole
SL valves close (DUB)
AV valves open
Cardiac Output:
Volume of blood pumped by Left Atrium
per min.
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Unit 1 Biology
Applying Biological Understanding: Heart Structure and Function
A person is diagnosed with a hole in the heart. This means that there is
a gap in the septum between the two ventricles of the heart.
a) On the diagram below indicate with an X the region affected with a
hole.(1 marks)
b)
(i)
Where does the right ventricle pump blood to?(1)
(ii) Where does the left ventricle pump blood to?(1)
c)
(i) How would the composition of the blood being pumped from the left
ventricle of a person with this condition compare with the blood
being pumped from the left ventricle of a normally function
heart? (1)
(ii) Explain the reason for this difference(2)
(iii)
Suggest and explain a possible symptom that a person with a
hole in the heart might experience due to this problem. (3)
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Unit 1 Biology
The Lymphatic System:
 Due to high pressure at the arterial end of capillaries, plasma is forced out through the
thin capillary walls.
 This fluid, similar to plasma but with fewer blood proteins, bathes the cells and is called
tissue fluid.
 Although some of this fluid enters the circulatory system at the venous end of the
capillary, much is left behind. It is one function of the Lymphatic system to return this fluid to
the blood circulatory system.
 The Lymphatic system is a non-circular system of drainage vessels which exists
throughout the body.
 Blood proteins and tissue fluid are taken up by the blind-ending, thin walled vessels
called lymphatics.
some blood proteins and
excess tissue fluid enter
the lymphatic
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Unit 1 Biology
 Lymphatics join to larger lymphatic vessels which unite into two ducts that empty their
contents into the vena cava, just before it joins the right atrium.
 The lacteals in the small intestines drain into lymphatics.
 Once the fluid has entered the lymphatic it is called LYMPH
 Lymph is similar to plasma, but which fewer blood proteins. It contains a large number of
lymphocytes (a type of white blood cell) that are made in lymph glands.
 Along the lymph vessels at various points are lymph nodes in which antibodies and new
white blood cells (leucocytes) are made.
Main drainage routs of the lymphatic system
 Transport of lymph in lymphatic vessels is similar to movement of blood in veins. Lymph
vessels have one-way valves to prevent back flow, and lymph is moved along due to the
contraction of surrounding muscles.
Deep Lymphatic vessel cut open to show valves
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Unit 1 Biology
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