Transcript Mamalian Circulation

Mammalian Circulation
The Heart
• The heart is a fist-sized, muscular organ that
pumps blood through the body.
• Every day, the heart pumps about 7,600
liters of blood, beating about 100,000 times.
Blood vessels are organized
into 3 primary cycles.
1. Cardiac Circulation: the route taken by
the blood within the heart.
2. Pulmonary Circulation: pathway of the
blood from the heart to the lungs and back.
3. Systemic Circulation: route from the heart
to the rest of the body. It includes all blood
vessels other than those associated with the
lungs.
A circulatory system has three
main elements:
1. Transport vessels: conduct fluid from one
area to another.
2. Transport medium: specialized fluid tissue
that carries substances around the body.
3. Pumping mechanism.
Mammalian Circulatory System
includes 3 main types of blood
vessels:
1.artery
2.vein
3.capillary
NOTE : The classification of blood vessels
also includes: arteriole (a small artery)and
venule (a small vein).
Arteries
• Carry blood away from the heart.
• Most carry oxygenated blood (pulmonary
artery is the exception).
• They contain elastic walls that expand as
blood passes through and snaps back.
• They have thicker layers of muscle than
veins (because blood flows through at high
pressure).
Veins
• carry blood toward the heart.
• Most veins carry deoxygenated blood.
• They lack elasticity but have a greater (blood) capacity
than the arteries.
• The blood flows through a vein at low pressure.
• They have valves every few centimeters that allow the
blood to flow in one direction.
• Skeletal muscles also aid in the blood movement.
• The pulmonary vein returns oxygenated blood from the
lungs back to the heart to be pumped into systemic
circulation.
Capillaries
• are a single layer of epithelial cells which
allows for easy diffusion.
• It forms a wall that regulates the movements
of fluids and other materials into and out of
the blood stream.
• Blood is pumped to the body capillaries via
the aorta, (the largest artery in the body).
Veins vs. Arteries
The Mammalian Heart :
• It is made up of cardiac muscle (that
contracts repeatedly without fatigue).
• It is surrounded by a protective layer called
the pericardium.
Mamallian Heart
Heart of a mammal is divided
into 4 chambers
Right and left Atria
Right and left Ventricles
Atria
- collecting chambers.
- receive blood from the lungs and body.
- pump blood to the ventricles.
• Ventricles
• - thick muscular wall.
• - pumping chambers that push blood out
through blood vessels and capillary beds.
Valves
• Bicuspid Valve (mitral)
• - located between left atrium and left ventricle.
• - has two parts or cusps.
• Tricuspid Valve
• - located between the right atrium and right
ventricle.
• - contains 3 cusps.
Valves
Aortic Semilunar Valve
- Located between the left ventricle and
the aorta
Pulmonary Semilunar Valve
- allows blood to travel from right ventricle
to the rest of the body.
Other Parts
• Septum
- wall that separates right and left ventricles.
• Pulmonary Vein
• - returns oxygenated blood from the lungs back
to the heart to be pumped into systemic
circulation.
• Pulmonary Artery
• - carries deoxygenated blood from the heart to
the lungs.
Flow of blood
• Inferior/superior vena cava  Right atrium
 Tricuspid valve (atrioventricular valve)
 Right ventricle  pulmonary Semilunar
valve  Pulmonary artery  Lungs 
Pulmonary vein  Left atrium  Bicuspid
valve (atrioventricular valve)  Left
venticle  aortic semilunar valve  Aorta
Blood: A Transport Medium
• Blood
-a collection of cells specialized to perform a
particular task within an organism.
-considered to be a tissue.
• Erythrocytes
red blood cells.
make up 44% of total blood volume.
adult male has 5.5 million rbc/mL of blood.
(female: 4.5 million).
specialized for oxygen transport
disk-shaped and contains no nucleus.
contains respiratory pigment hemoglobin.
rarely lives more than 3-4 months.
• Hemoglobin
iron-containing molecule that binds with
oxygen.
allows oxygen to be transported in the
blood.
• White Blood Cells
also known as leucocytes.
-
make up approximately 1% of blood volume but increases when
fighting infection.
- contain a nucleus and appear colorless.
- two most important wbc are:
1. Macrophages
- phagocytic cells that pass through the walls of capillaries to engulf and
digest pathogens.
2. Lymphocytes
- non-phagocytic cells that play a role in body’s immune response that
enables body to recognize and fend off specific pathogens.
• Platelets
not cells.
-fragments of cells that were created when
larger cells in bone marrow break apart.
fragments break down quickly in blood (last
only a week to 10 days).
- play an important role in blood clotting.
•
1.
Blood Plasma
fluid portion of the blood.
medium in which blood is suspended.
contain plasma proteins.
Albumin
- keeps water from entering or leaving the blood and
entering the surrounding cells by osmosis.
2. Fibrinogen
- clotting of blood.
3. Globulins
- transport of proteins and other substances from one part
of the body to another.