Transcript The Circulatory System

The problem
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How do we get nutrients and gases to every
cell of the body?
The Circulatory System
What is the circulatory system?
What are its functions?
Circulatory system - structure
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Consists of
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Blood – the medium
The Heart – the pump
Blood Vessels – the pathways
Function
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Transports substances within the body
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Nutrients/waste products
Gases – oxygen/carbon dioxide
Hormones
Immune system
Also assists with temperature regulation
Blood
Plasma
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Makes up 55% of blood volume
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90% water
7% plasma protein
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2% dissolved solutes
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Fibrinogen, albumins and globulins – assist in transport
and clotting
Nutrients, wastes, hormones
1% dissolved salts
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Sodium, calcium, potassium, and magnesium
chloride, bicarbonate, phosphate and sulfate
Formed elements
Formed Elements
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Erythrocytes (gk Erythro = red)
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Leukocytes (gk Leuco = white)
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Red blood cells
Carry oxygen
White blood cells
Immune system - defence
Platelets
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Clotting
Red Blood Cells
Red Blood Cells
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aka erythrocytes
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Carry oxygen and carbon dioxide
Biconcave
Do not have a nucleus
Produced in bone marrow and stored in the
spleen
Contain hemoglobin – the protein which carries
oxygen and carbon dioxide
Hemoglobin
Hemoglobin
Hemoglobin
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Each hemoglobin has 4 subunits
Each subunit has an iron atom which
associates with one oxygen/carbon dioxide
molecule
A shortage of hemoglobin is called anemia
White Blood Cells
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Part of the immune system
Defends the body against invaders
Pus can form when there is an infection
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A mixture of living and dead white blood cells and
bacteria
Responds to infection by:
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Enveloping foreign bodies
Destroying infected cells
Signalling the body – inflammation, fever
Platelets
Platelets
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Contain the protein fibrinogen
Responsible for clotting
Blood Types
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What are they?
How are they determined?
Blood types
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The four blood types are A, B, AB and O.
They are determined by the presence (or
absence) of the A and B antigens on the cell
A separate antigen (Rh factor) determines
whether or not it is positive or negative
Donating Blood
Donor
A
B
AB
O
A
yes
no
no
yes
B
no
yes
no
yes
AB
yes
yes
yes
yes
O
no
no
no
yes
Recipient
The Heart
Superior Vena Cava
Arteries
Aorta
Pulmonary Artery (right)
Pulmonary Artery (left)
Pulmonary Vein (left)
Pulmonary Veins (right)
Left Atrium
Semi-lunar Valve
[pulmonary]
Right Atrium
Atrioventricular (A-V) Valve
[tricuspid]
Atrioventricular (A-V) Valve
[bicuspid/Mitral]
Semi-lunar Vavle
[aortic]
Right Ventricle
Left Ventricle
Inferior Vena Cava
Septum
The Heart
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Muscled organ used to pump blood
Consists of 4 chambers
Two types of chambers – atria and ventricles
Heart can be divided into left and right sides
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Septum – tissue that separates left and right sides
Atria and Ventricles
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Two types of chambers
Atria
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Receive blood
Ventricles
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Pump blood
Left and Right Sides
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Left side
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Receives deoxygenated blood from body
Pumps it to lungs
Right side
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Receives oxygenated blood from lungs
Pumps it to the body
Two loops
Lungs/capillaries/alveoli
Pulmonary Veins
Aorta
Pulmonary arteries
Left atrium
Right atrium
Right Ventricle
Vena cava
veins
venules
Left Ventricle
arteries
arterioles
capillaries
Systemic and Pulmonary Circuits
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Blood travels along two distinct pathways
SYSTEMIC CIRCUIT
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From the heart to all the tissues and back
Leaving the heart with oxygenated blood and
returning with deoxygenated blood
PULMONARY CIRCUIT
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From the heart to the lungs and back
Leaving the heart with deoxygenated blood and
returning with oxygenated blood
Blood Vessels
Blood Vessels
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Arteries – carry blood away from the heart
Veins – carry blood towards heart
Capillaries – site of diffusion
Arteries
Arteries
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Carry blood away from the heart
Thick, muscular walls – epithelial, muscle and
connective tissue
Elastic
Found deep within muscle tissue
Blood propelled by heart, blood pressure
Arteries branch into smaller arterioles
Veins
Veins
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Carry blood towards the heart
Thin, elastic walls
Found near the surface of the skin
Contain valves to ensure blood only flows in
one direction
Blood is propelled by muscular contraction
Smaller veins called venules collect blood
from capillaries
Capillaries
Capillaries
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Site of nutrient exchange/diffusion
Extremely narrow – only one red blood cell
may pass at a time
Extremely thin walls
Beds of extremely dense, diffuse blood
vessels provide surface area for diffusion
Blood Pressure
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The force of the blood on the walls of the
blood vessels
Systolic – while the heart is contracting
Diastolic – while the heart is relaxing
Measuring Blood Pressure
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Measured with a SPHYGMOMANOMETER
and a stethoscope
Measuring blood pressure
No pulse
Cuff cuts off circulation
Systolic Pressure
Pulse
Systolic pressure able
to overcome cuff pressure
Diastolic Pressure
Cuff Pressure
No pulse
Both systolic and diastolic
pressures are greater than
Cuff pressure.
Blood flows smoothly
Measuring Blood Pressure
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Inflate cuff until circulation cut off
Slowly release pressure
Listen
Pulse is heard when systolic pressure is
reached
Pulse stops when diastolic pressure is
reached
Blood Pressure
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A normal systolic pressure is 120 mm Hg
A normal diastolic pressure is 80 mm Hg
Blood Pressure
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What is your blood pressure?
What factors do you think affect blood
pressure?
Design and conduct an experiment to
determine one of the factors affecting blood
pressure.