Cardiovascular System The cardiovascular system consists of the heart, blood vessels, - PowerPoint Presentation

Slide1

Cardiovascular SystemThe cardiovascular system consists of the heart, blood vessels, and the approximately 5 liters of blood that the blood vessels transport. Responsible for transporting oxygen, nutrients, hormones, and cellular waste products throughout the body.

The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs. In the human heart there is one atrium and one

ventricle

for each circulation, and with both a systemic and a pulmonary circulation there are four chambers in total:

left atrium

,

left ventricle

,

right atrium

and

right ventricle

. The right atrium is the upper chamber of the right side of the heart. The blood that is returned to the right atrium is deoxygenated (poor in oxygen) and passed into the right ventricle to be pumped through the pulmonary artery to the lungs for re-oxygenation and removal of carbon dioxide. The left atrium receives newly oxygenated blood from the lungs as well as the pulmonary vein which is passed into the strong left ventricle to be pumped through the aorta to the different organs of the body.

The Blood VesselsIn class we talked about three types of blood vessels:

Arteries

Capillaries

Veins

Arteries

are blood vessels that carry oxygen rich blood AWAY from the

heart.

Capillaries

are tiny blood vessels as thin or thinner than the hairs on your head. Capillaries connect arteries to veins. Food substances(nutrients), oxygen and wastes pass in and out of your blood through the capillary walls.

Veins

carry blood back toward your

heart.

StructureThe arteries and veins have three layers, but the middle layer is thicker in the arteries than it is in the veins:

Tunica

intima

(the thinnest layer): a single layer of simple

squamous

endothelial cells

glued by a

polysaccharide

intercellular matrix, surrounded by a thin layer of

subendothelial

connective tissue

interlaced with a number of circularly arranged elastic bands called the

internal elastic lamina

.

Tunica media

(the thickest layer in arteries): circularly arranged elastic fiber, connective tissue, polysaccharide substances, the second and third layer are separated by another thick elastic band called external elastic lamina

Tunica media may (especially in arteries) be rich in vascular smooth muscle

, which controls the caliber of the vessel.

Tunica adventitia

: (the thickest layer in veins) entirely made of connective tissue. It also contains

nerves

that supply the vessel as well as nutrient capillaries (

vasa

vasorum) in the larger blood vessels.

CapillaryA capillary is an extremely small blood vessel located within the tissues of the body, that transports blood from

arteries

to

veins

. Capillaries are most abundant in tissues and organs that are metabolically active. For example,

muscle tissues

and the kidneys have a greater amount of capillary networks than do

connective tissues . Capillary SizeCapillaries are so small that red blood cells can only travel through them in single file. Capillaries measure in size from about 5-10 microns in diameter. Capillary walls are thin and are composed of endothelium (a type of simple

squamous

epithelial

tissue

). Oxygen, carbon dioxide, nutrients and wastes are exchanged through the thin walls of the capillaries.

Capillary MicrocirculationCapillaries play an important role in microcirculation . Microcirculation deals with the circulation of blood from the

heart

to arteries, to smaller arterioles, to capillaries, to

venules

, to veins and back to the heart.

The flow of blood in the capillaries is controlled by structures called

precapillary

sphincters. These structures are located between arterioles and capillaries and contain muscle fibers that allow them to contract. When the sphincters are open, blood flows freely to the capillary beds of body tissue. When the sphincters are closed, blood is not allowed to flow through the capillary beds. Fluid exchange between the capillaries and the body tissues takes place at the capillary bed.

Blood is a bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. When it reaches the lungs, gas exchange occurs when carbon dioxide is diffused out of the blood into the pulmonary alveoli and oxygen is diffused into the blood. This oxygenated blood is pumped to the left hand side of the heart in the pulmonary vein and enters the left atrium. From here it passes through the mitral valve, through the ventricle and taken all around the body by the aorta. Blood contains antibodies, nutrients, oxygen and much more to

help

the body

work

Blood performs many important functions within the body including:Supply of oxygen to tissues (bound to hemoglobin, which is carried in red cells)Supply of nutrients such as glucose, amino acids, and fatty acids (dissolved in the blood or bound to plasma proteins (e.g., blood lipids))Removal of waste such as carbon dioxide, urea, and lactic acidImmunological functions, including circulation of white blood cells, and detection of foreign material by antibodies

Coagulation, the response to a broken blood vessel, the conversion of blood from a liquid to a semi-solid gel to stop bleeding.Messenger functions, including the transport of hormones and the signaling of tissue damageRegulation of body pHRegulation of core body temperatureHydraulic functions

PlasmaMain article: Blood plasma

About 55% of blood is

blood plasma

, a fluid that is the blood's liquid medium, which by itself is straw-yellow in color. The blood plasma volume totals of 2.7–3.0 liters (2.8–3.2 quarts) in an average human. It is essentially an

aqueous

solution containing 92% water, 8% blood plasma

proteins

, and trace amounts of other materials. Plasma circulates dissolved nutrients, such as glucose, amino acids, and fatty acids (dissolved in the blood or bound to plasma proteins), and removes waste products, such as

carbon dioxide

,

urea

, and

lactic acid

Other important components include:Serum albumin

Blood-clotting factors (to facilitate

coagulation

)

Immunoglobulins

(antibodies)

lipoprotein

particlesVarious other proteins

Various

electrolytes

(mainly

sodium

and

chloride

)

The term

serum

refers to plasma from which the clotting proteins have been removed. Most of the proteins remaining are albumin and

immunoglobulins

.

Thank You