Title: CIRCULATORY SYSTEM
1CIRCULATORY SYSTEM
2Circulatory System
- Circulatory system
- Efficient distribution system
- Network of 100,000 km of blood vessels
- Supplies cells with nutrients and oxygen and
removes carbon dioxide and waste products - Transports hormones
- Plays an important role repairing tissues and
protecting the body from infection
3Organs of the Circulatory System
- Blood Type of connective tissue (cells
liquid) - Heart Multi-chambered, muscular organ
- Overall flow of blood via blood vessels ? from
the heart to the tissues - throughout the body back to the
- heart
- - Body contains 5 L of blood
43 Types of Blood Vessels
- Capillaries
- Microscopic blood vessels- make contact with all
cells of the body - Walls of capillaries consist of a thin layer of
epithelial tissue ? enables diffusion of
nutrients and oxygen out of the blood the
diffusion of waste products into the blood - Arteries
- Blood flows from the heart to the capillaries
through thick walled blood vessels arteries - Walls of arteries epithelial tissue wrapped in
layers of smooth muscle and connective tissue - Muscle tissue enables arteries to constrict
dilate Blood in arteries is under pressure due
to the hearts pumping action
53 Types of Blood Vessels
- 3. Veins
- Blood returns from the capillaries to the heart
through vessels veins - Walls of veins consist of epithelial tissue
surrounded by smooth muscle connective tissue
but muscle layer is thinner than that in arteries - Blood is under little pressure
- Contracting skeletal muscles squeezes the
- veins and forces blood back to the heart
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7Chemical Exchange between Blood Body Tissues
- Most cells are no further than 10 micrometers
from a capillary and the blood inside - Capillary network
- Critical to accomplishing the main functions of
the circulatory system - Distribution of oxygen nutrients, and removal
of waste products - Cells in body tissues ? surrounded by
interstitial fluid
8Chemical Exchange between Blood Body Tissues
- Substances in capillaries do not enter tissue
cells directly - First Substances in capillaries enter the
interstitial fluid - Second Substances in the interstitial fluid then
enter the cells -
9Chemical Exchange between Blood Body Tissues
- Exchange of substances between blood
interstitial fluid occurs in several ways - Small molecules (oxygen, carbon dioxide) ?
diffuse across the membrane or pass through gaps
between the epithelial cells of the capillary
wall - Oxygen nutrients move from the blood into the
interstitial fluid - Carbon dioxide other small waste products move
from the interstitial fluid into the blood - Larger molecules move across the membranes by
exocytosis and endocytosis
10Chemical Exchange between Blood Body Tissues
- Exchange of substances between blood
interstitial fluid occurs in several ways - Blood pressure ? forces fluid through the
capillary wall - ? At the artery end of a capillary ? blood
pressure forces water, small solutes, and some
dissolved proteins through the gaps between the
cells However, blood cells larger proteins are
too large to pass easily through the openings ?
remain in the capillary - ? Result Vein end of the capillary in hypertonic
compared to the surrounding interstitial fluid ?
Thus, water reenters the vein end of the
capillary via osmosis Blood pressure is very low
at the vein end of the capillary, so it does not
oppose the flow of fluid back into the capillary -
11Blood consists of Cells suspended in Plasma
- Blood
- Highly specialized tissue
- Part liquid, part cellular material
- Plasma
- Composes 55 of the volume of blood
- Plasma 90 water Other 10 dissolved salts,
proteins, transport substances
12Blood consists of Cells suspended in Plasma
- Red blood cells (Erythrocytes)
- Constitutes the remaining 45 of the blood volume
- Carry oxygen from the lungs to all the tissues in
your body - Each RBC ? contains 250 million molecules of
hemoglobin (Protein that temporarily stores
oxygen for delivery to cells) - Hemoglobin ? Contains iron ? Oxygen molecules
bind to the iron portion (heme group) of the
hemoglobin molecule
13Red Blood Cells
- Red blood cells (Erythrocytes)
- Produced in the bone marrow
- Distinctive shape due to the loss of their nuclei
and mitochondria ? shape flat disk, curves
inward in the middle ? structure provides
increased surface area for oxygen transport - Life span of a RBC 100-120 days
14Blood consists of Cells suspended in Plasma
- White blood cells (Leukocytes)
- Responsible for fighting infection and preventing
the growth of cancer - When an infection invades your body ? of WBCs
increases - Most of the action of the WBC takes place outside
the blood vessels in the interstitial fluid
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163 Functions of Blood
- Blood
- Carries oxygen, nutrients, and hormones
- Removes waste (carbon dioxide)
- Fights infection
17Blood consists of cells suspended in plasma
- Blood
- Connective tissue
- Flows through blood vessels
- Five liters of blood
- Takes 1 minute to make a complete circuit
- Composed of
- 55 Plasma
- 45 RBCs
18Blood consists of cells suspended in plasma
- Plasma (45)
- 90 water
- 10 dissolved salts, proteins, and other
substances - RBCs
- Erythrocytes
- Most numerous cells in blood
- 5 million RBCs in 1 drop of blood
- Contains hemoglobin
- Produced in the bone marrow (2 million per
second) - Replaced every 120 days
19Blood consists of cells suspended in plasma
- Hemoglobin
- Protein that binds with oxygen for transport to
cells - Contains iron which contains a high affinity for
oxygen
20Blood consists of cells suspended in plasma
- WBCs
- Leukocytes
- Fight infection and prevents growth of cancer
- 4,000-11,000 WBCs in 1 drop of blood
- Infection increases the number of WBCs
- Most action takes place in the interstitial fluid
21Blood consists of cells suspended in plasma
- Blood clotting
- Platelets help with blood clotting
- Originate from the bone marrow
- 250,000 500,000 in a drop of blood
- Stick to damaged site
- Release clotting factors
- Fibrin produced (Protein)
- Patch forms and dries into a scab