Transcript White Blood Cells

Circulatory System
The 3 main parts of the
circulatory system
1. The Heart
2. The blood vessels
3. Blood
Two Pathways
• Pulmonary Circulation
– Carries blood to lungs and back
• Systemic Circulation
– Carries blood to body and back
Capillaries of head and arms
Superior vena cava
Aorta
Pulmonary artery
Pulmonary vein
Capillaries of right lung
Capillaries of left
lung
Inferior vena cava
Capillaries of abdominal organs
and legs
The 3 main parts of the
circulatory system
1. The Heart
2. The blood vessels
3. Blood
Circulatory System
HEART
The Heart
Chambers of the Heart
The heart is actually two separate pumps.
The left side pumps blood to the body (systemic
circulation)
The right side pumps blood to the lungs (pulmonary
circulation)
The Structures of the Heart
Superior Vena Cava
Large vein that brings oxygen-poor blood from the
upper part of the body to the right atrium
Aorta
Brings oxygen-rich blood from the left
ventricle to the rest of the body
Pulmonary Arteries
Bring oxygen-poor blood
to the lungs
Pulmonary Veins
Bring oxygen-rich blood from each of
the lungs to the left atrium
Left Atrium
Pulmonary Valve
Prevents blood from flowing back
into the right ventricle after it has
entered the pulmonary artery
Aortic Valve
Prevents blood from flowing
back into the left ventricle after
it has entered the aorta
Right Atrium
Tricuspid Valve
Prevents blood from flowing back
into the right atrium after it has
entered the right ventricle
Inferior Vena Cava
Vein that brings oxygen-poor
blood from the lower part of the
body to the right atrium
Mitral Valve
Prevents blood from flowing back
into the left atrium after it has
entered the left ventricle
Left Ventricle
Septum
Right Ventricle
Types of blood vessels
Arteries
- Carry blood away from the heart
- The Aorta is the largest artery
Veins
- Carry blood away from the heart
- veins contain valves
- the vena cava is the largest veins
Capillaries
- Known as the ‘Distribution Pipes”
Arteries
Arteries have a thick, elastic layer to allow stretching and absorb pressure. The
wall stretches and recoils in response to pumping, thus peaks in pressure are
absorbed.
The arteries maintain pressure in the circulatory system much like a balloon
maintains pressure on the air within it. The arteries therefore act as pressure
reservoirs by maintaining (storing) pressure.
The elastic layer is surrounded by circular muscle to control the diameter and
thus the rate of blood flow. An outer layer of connective tissue provides
strength.
Arteries:
carries blood Away from heart
–
–
–
–
Large
Thick-walled, Muscular
Elastic
Oxygenated blood
•
Exception Pulmonary Artery
– Carried under great pressure
– Steady pulsating
Arterioles: smaller vessels, enter tissue
Artery vs. Vein
Veins
The diameter of veins is greater than that of arteries.
The blood pressure in the veins is low so valves in veins help prevent
backflow.
The contraction of skeletal muscle squeezes the veins and assists with
moving blood back to the heart.
The vena cava returns blood to the right atrium of the heart from the
body. In the right atrium, the blood pressure is close to 0.
Varicose veins develop when the valves weaken.
Veins act as blood reservoirs because they contain 50% to 60% of the
blood volume.
Smooth muscle in the walls of veins can expand or contract to adjust
the flow volume returning to the heart and make more blood available
when needed.
Veins:
Carries blood to heart
–
Carries blood that contains
waste and CO2
•
–
–
Exception pulmonary vein
Blood not under much pressure
Valves to prevent much gravity
pull
Venules: larger than capillaries
Capillaries
–
–
–
–
Smallest vessel
Microscopic
Walls one cell thick
Nutrients and gases diffuse here
Blood consists of three types of cells:
oxygen-bearing red blood cells, diseasefighting white blood cells, and bloodclotting platelets, all of which are carried
through blood vessels in a liquid
called -----------.
Plasma is yellowish and consists of water,
salts, proteins, vitamins, minerals,
hormones, dissolved gases, and fats.
_________ have thicker walls than veins to withstand the
pressure of blood being pumped from the heart.
Blood in the veins is at a lower pressure, so veins have one-way
valves to prevent blood from flowing backwards away from the
heart.
___________ the smallest of blood vessels, are only visible by
microscope—ten capillaries lying side by side are barely as thick
as a human hair. If all the arteries, veins, and capillaries in the
human body were placed end to end, the total length would
equal more than 100,000 km (more than 60,000 mi)—they could
stretch around the earth nearly two and a half times.
Three types of blood vessels form a complex network of tubes
throughout the body. __________ carry blood away from the heart,
and _________carry it toward the heart. ____________are the tiny
links between the arteries and the veins where oxygen and nutrients
diffuse to body tissues.
The inner layer of blood vessels is lined with endothelial cells that
create a smooth passage for the transit of blood.
This inner layer is surrounded by connective tissue and smooth muscle
that enable the blood vessel to expand or contract.
Blood vessels expand during exercise to meet the increased demand for blood
and to cool the body. Blood vessels contract after an injury to reduce bleeding
and also to conserve body heat.
The composition of blood
1. The plasma (Fluid) – makes up 55% of the blood volume
2. The solids (cells) – makes up 45% of the blood volume
Blood Plasma (fluid)
- 97% water
- other 3% (antibodies and protein & nutrients and wastes)
Blood Solid (cells)
- Red Blood Cells – Carry O2 and contain hemoglobin
- White Blood Cells – Attack bacteria & other invaders
- Platelets – Control the blood clothing process
Liquid Portion Carries
• Blood cells
– Erythrocytes (RBC - red blood cells)
– Leucocytes (WBC - white blood cells)
• Platelets (non cellular particles)
• Proteins
– Enzymes
– Hormones – Endocrine System
• Nutrients - Digestive System
• Gases - Respiratory System
• Inorganic salts
Blood is made up of a number of types of cells:
Plasma: Plasma is a straw-coloured fluid in which blood cells are
suspended. It is made up of approximately 90% water as well as
electrolytes such as sodium and potassium and proteins.
Red Blood Cells (Erythrocytes): The main function of red blood cells
is to carry oxygen. RBC's contain a protein called Haemoglobin. This
combines with oxygen to form Oxyhaemoglobin. Each RBC has a
lifespan of approximately 120 days before it gets broken down by the
spleen. New RBC's are manufactured in the bone marrow of most
bones. There are approximately 4.5-5 million RBC's per micro-litre of
blood.
White Blood Cells (Leucocytes): There a number of types of white
blood cells, although the function of all of them is to help fight
disease and infection. They typically have a lifespan of a few days
and there are only 5-10 thousand WBC's per micro-litre of blood.
Platelets (Thrombocytes): Platelets are disc shaped cell fragments
which are involved in clotting the blood to prevent the excess loss of
body fluids.
Red Blood cells
Erythrocytes (RBC)
• Transporters of
– Oxygen
– Carbon Dioxide
• RBC
– Lack a nucleus
– Contain hemoglobin
– Disk-shaped
• RBC are produced in red bone
marrow of
–
–
–
–
ribs,
humerus,
femur,
sternum, and other long bones
• Lives for 120 days
• Old RBC are destroyed in liver and
spleen
Leukocytes (WBC)
•
WBC fight infection
–
•
•
•
Less abundant
Large cells
Some live for months
–
•
•
Attack foreign
substances
Most just a few days
Several types
ALL contain nuclei
Platelets
•
•
•
•
•
PLATELETS are for CLOTTING blood
Cell fragments
Produced in bone marrow
Short life span (1 week)
Fibrin (sticky network of protein fibers)
– Form a web trapping blood cells
The Blood
• Body contains 4-6 L
• Consists of
–
–
–
–
Water
Red Blood Cells
Plasma
White blood cells and
platelets
Plasma
Platelets
White blood
cells
Red blood cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That Has
Been Centrifuged
Plasma
Platelets
White blood
cells
Red blood cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That Has
Been Centrifuged
Plasma
Platelets
White blood
cells
Red blood cells
Whole Blood Sample
Sample Placed in Centrifuge
Blood Sample That Has
Been Centrifuged
Parts of the Blood
Blood Clotting
Break in Capillary Wall
Clumping of Platelets
Clot Forms
Blood vessels injured.
Platelets clump at the site and
release thromboplastin.
Thromboplastin converts
prothrombin into thrombin..
Thrombin converts fibrinogen
into fibrin, which causes a clot.
The clot prevents further loss
of blood..
What is the function of blood??
1. Transportation:
The blood carries other substances around the body inside arteries, veins and
capillaries.
These include gasses (Oxygen and Carbon Dioxide), waste products (water, urea),
hormones, enzymes and nutrients (glucose, amino acids, vitamins and minerals).
The blood flows through the circulatory system.
2. Maintaining Homeostasis:
Altering the blood flow to the skin can help to reduce body temperature.
Transportation of enzymes which are used to maintain our internal environments.
3. Immunity and defense:
White blood cells fight infection and platelets help repair damage and clot the
blood
What is the circulatory system?
- transports food, hormones, metabolic wastes,
and gases (oxygen, carbon dioxide) to and from
cells.
Components of the circulatory system include:
BLOOD: consisting of liquid plasma and cells
BLOOD VESSELS (vascular system): the "channels" (arteries,
veins, capillaries) which carry blood to/from all tissues.
Arteries carry blood away from the heart.
Veins return blood to the heart.
Capillaries are thin-walled blood vessels in which gas/
nutrient/ waste exchange occurs.
HEART : a muscular pump to move the blood
What is the circulatory system?
carries blood and dissolved substances to
and from different places in the body.
The Heart has the job of pumping these
things around the body.
The Heart pumps blood and substances
around the body in tubes called blood
vessels.
The Heart and blood vessels together make up the Circulatory System.
No Circulatory Systems
• In simple organisms in moist environments
Circulation
• Movement of fluid through an organism
• Circulatory system
– Transport system
– Uses fluid to move substances
Respiratory system via Circulatory system
The arteries, veins, and capillaries are divided into two systems of
circulation: systemic and pulmonary.
The systemic circulation carries oxygenated blood from the heart to all
the tissues in the body except the lungs and returns deoxygenated
blood carrying waste products, such as carbon dioxide, back to the
heart.
The pulmonary circulation carries this spent blood from the heart to the
lungs.
In the lungs, the blood releases its carbon dioxide and absorbs oxygen.
The oxygenated blood then returns to the heart before transferring to
the systemic circulation.
Physical Activity
With exercise, metabolism speeds up and because of this the muscles require
more oxygen
So the heart beats faster to supply the muscles with more oxygen-rich blood
In turn the speed of blood flow increases.
Blood Pressure
Blood pressure is defined as the force exerted by the blood against the vessel wall.
Blood pressure is highest in arteries and gradually decreases as it passes through
arterioles, capillaries, venules and finally, veins.
Blood pressure is also variable and can increase due to exercise where the cardiac
output increases thus forcing more blood through the arteries or by altering the
peripheral resistance. This occurs by vasoconstriction, increases in blood viscosity
(thickness) and changes in shape or size of the vessels. The regulation of blood
pressure is the responsibility of the sympathetic and parasympathetic nervous
systems.
Blood Pressure
• Blood against the blood vessel’s walls
– The systolic pressure refers to
• the pressure recorded while the ventricles pump the
blood.
– The diastolic pressure refers to
• the pressure recorded as the ventricles fill with blood.
• A normal blood pressure is 120/80
Digestive system via Circulatory system
The circulatory system also transports nutrients derived from digested
food to the body.
Nutrients enter the bloodstream by passing through the walls of the
intestine - absorbed through a network of capillaries and veins that
drain the intestines, called the hepatic portal circulation.
The hepatic portal circulation carries the nutrients to the liver for
further metabolic processing.
The liver also cleans the blood by removing waste products and toxins.
The circulatory system plays an important role in regulating
body temperature. During exercise, working muscles generate
heat. The blood supplying the muscles with oxygen and
nutrients absorbs much of this heat and carries it away to
other parts of the body. If the body gets too warm, blood
vessels near the skin enlarge to disperse excess heat outward
through the skin. In cold environments, these blood vessels
constrict to retain heat.
Blood vessels expand during exercise to meet the
increased demand for blood and to cool the body.
Blood vessels contract after an injury to reduce
bleeding and also to conserve body heat.
Functions of the circulatory system:
Distribute nutrients,
Transport and exchange oxygen and carbon dioxide,
Remove waste materials,
Distribute secretions of endocrine glands,
Prevent excessive bleeding,
Prevent infection, and
Regulate body temperature.
What happens when you mix blood types?
• Plasma contains proteins that
correspond to the shape of the
different antigens
• If you mix one type with the
wrong one, you get CLUMPING
• Type O is the universal donor
• Type AB is the universal acceptor
What Makes Our Blood Type?
Blood Transfusions
Blood Type of
Donor
Blood Type of Recipient
A
B
AB
O
A
B
AB
O
Unsuccessful transfusion
Successful transfusion
Rh Factor
• Rhesus factor (Rh), also inherited
– Rh+ (have antigen)
– Rh- (NO antigen)
• Can cause complications in pregnancies
– mother Rh- 1st baby Rh+ : blood mixes with
mother; mother’s body makes anti-Rh+ antibodies
– 2nd Rh + body attacks baby
– Now have medicine to prevent antibody formation
How about the circulatory system
in animal? Fish? Amphibians?
Reptilians? Insects?
Humans cannot survive for more than a
few minutes without O2. Why?