Transcript Document

Unit 9
Circulatory
System:
Blood
CIRCULATORY SYSTEM
•Heart
•Veins
•Capillaries
•Arteries
•lymph vessels
•lymph glands
Functions of the circulatory system:
Transport and exchange oxygen, nutrients
and carbon dioxide
Remove waste materials
Prevent infection
Regulate body temperature.
Anatomy and Physiology
of the Blood
Blood is an important component
of the circulatory system.
Anatomically and functionally,
blood is a connective tissue.
Components of Blood
55% - Plasma: a yellow liquid component of blood
1. water (90%)
2. solids (10%) - proteins,
glucose, clotting factors,
mineral ions, hormones,
and carbon dioxide (waste)
Components of Blood
45% - Cellular Component
•Erythrocytes (RBC)
•contain hemoglobin,
• red color
•carry oxygen
•Leukocytes (WBC)
•help the body fight bacteria and infection
•formed in the small ends of bones
•Leukocyte # increases when a tissue is damaged or has an infection
•Thrombocytes (platelets)
•Aid the formation of blood clots by releasing various protein
substances
•contains fibrin - allows blood to clot (coagulate)
Erythrocytes (RBC)
Thrombocytes (platelets)
Leukocytes (WBC)
ABO Blood Types
•Classified based on certain antigens and antibodies found on surface
of red blood cells
•Agglutination
•RBC coagulate
•Occurs when two different blood types combine
Parent Alleles
A
B
O
A
B
O
AA
(A)
AB
(AB)
AO
(A)
AB
(AB)
BB
(B)
BO
(B)
AO
(A)
BO
(B)
OO
(O)
ABO
Blood Type
Antigen
A
Antigen
B
Antibo
dy
anti-A
Antibody
Anti-B
A
yes
no
no
yes
B
no
yes
yes
no
O
no
no
yes
yes
AB
yes
yes
no
no
Human ABO Blood Types
Image courtesy of Wikipedia.
Rh Factor
•Does not affect your health except during pregnancy
•A woman is at risk when she is Rh- and her partner Rh+
•This combination can produce a child who is Rh+
•mother to creates antibodies against the Rh factor, thus treating an Rh+
baby like an intruder in her body. If this happens the mother is said to be
sensitized.
•Rh antibodies will then attack an Rh+ baby's blood, causing it to breaking
down the red blood cells of the baby and anemia will develop.
•In severe cases this hemolytic disease can cause illness, brain damage
and even death.
•Rh immunoglobulin (RhIg) is a blood product given via injection to help the
Rh- mother by suppressing her ability to react to the Rh+ red cells
Rh Factor
Rh+
Rh-
RBC Type
Antibodies
present
None
Anti-Rh
Antigens present
Rh antigen
None
Parts of the Circulatory System
•Pulmonary circulation - takes the blood from the heart to the
lungs, where it is oxygenated, and returns it to the heart.
Parts involved: heart, pulmonary arteries,
capillaries of the lungs, and pulmonary veins.
• Systemic circulation - flow of oxygenated blood from the
heart to the tissues in all parts of the body and the return of
un-oxygenated blood back to the heart.
Parts involved: arteries, capillaries, and veins
Three types of blood vessels
Photo from U. S. Federal Government courtesy of Wikipedia.
→ arteries → arterioles → capillaries → venules → veins →
Three types of blood vessels: Arteries
• Arteries - carry blood, rich in oxygen, from the heart to
other parts of the body. (Arteries = Away)
-Three tissue layers thick: allow to withstand blood
pressure
-Highly elastic (allows dilation and constriction)
- Aorta: largest artery
-Divide into arterioles
-Where pulse is found
Note: All arteries carry oxygenated blood except for the
pulmonary artery that carries deoxygenated blood to the
lungs.
Pulse
•only felt in arteries
•spurt of high pressure blood passing along the arteries when the left ventricle contracts
•elastic walls of arteries stretch
•When the pulse has passed, the walls contract and this helps push the blood along.
•easily felt at certain places where an artery passes near the surface of the body
(pulse/pressure points)
•strongest near the heart and becomes weaker as it travels away from the heart
•No pulse in capillaries or veins
•Pulse Rate / Heartbeat /Heart rate
-Measured in bpm (beats per minute)
-Average Resting Adult: 60-80 bpm
-Tachycardia – exceeds normal range
-Bradycardia – below normal range
-Men: 68-75 bpm
-Women: 72-80 bpm
-Athletes: 40-60 bpm
•Factors increase heart rate
-dehydration
-weight
-exercise
-smoking
-caffeine
Blood Pressure
•Pressure of blood against the walls of the main arteries
•Pressure highest when left ventricle contracts, forcing blood into atrium
•Systole – contraction of left ventricle
•Pressure lowest between pulses, during relaxtion (ventricles refill)
•Diastole – relaxation of ventricle
•BP = systole/diastole = 120/80 mmHg = normal BP
Hypertension – high blood pressure
Hypotension – low blood pressure
Sphygmomanometer – measures
blood pressure
Capillaries
•connect arteries to veins; specifically arterioles to venules
•Gas Exchange: distribute the nutrients and oxygen to the
body's tissues and remove deoxygenated blood and wastes
•Extremely thin: only one cell thick
•Capillary beds are so dense that no living cell is far from its
supply of oxygen and food.
Capillary Bed
Interaction of molecules flowing in and out of blood at a capillary bed.
Veins
•return blood to the heart from all parts of the body.
•No pulse
•Low pressure
•Less elastic and have thinner walls than arteries
•Have the same three layers as arteries
•Have to overcome gravity
•One-way valves – prevent backflow
•Skeletal muscle contractions
•carry deoxygenated blood towards the lungs where oxygen is received
via the pulmonary capillaries.
Note: The pulmonary vein that carries oxygenated blood from
the lungs to the left atrium of the heart is an exception.
Major Arteries & Veins:Pulmonary Circulation
•Pulmonary Artery and Vein – the only arteries
that carry deoxygenated blood; carries it to the
lung
Major Arteries & Veins:Systemic Circulation
•Aorta
•the main artery that pumps blood into the body
•largest artery in body
•Inferior/Superior Vena cava
•allows blood to be returned to the heart
•largest vein in body
•Arteries and veins to and from many organs often run alongside each other
and have the same name
•Renal artery and vein – kidney
•Femoral artery and vein - hind limbs (legs)
•Subclavian artery and vein - forelimbs (arms)
•Carotid artery - to the head
•Jugular vein – from the head
•Hepatic portal vein
•carries blood from the intestines to the liver
•only vessel that transports blood from one organ to another rather
than to or from the heart like arteries or veins.
Blood Disorders
• Anemia
– Causes
• Loss of blood due to injury
• Infestations of blood-sucking parasites
• Low levels of red cell production and hemoglobin
• poor nutrition
– Symptoms
• Chest pain
• Dizziness or light-headedness (especially when standing up or with
exertion)
• Fatigue or lack of energy
• Headaches, problems concentrating
• Shortness of breath (especially during exercise)
– Treatment
• Blood transfusions
• Corticosteroids or other medicines that suppress the immune system
• Erythropoietin, a medicine that helps your bone marrow make more
blood cells
• Supplements of iron, vitamin B12, folic acid, or other vitamins and
minerals
Sickle Cell Anemia
•
•
Causes
– an abnormal type of hemoglobin is present which distorts the shape of red blood
cells,
– These fragile, sickle-shaped cells deliver less oxygen to the body's tissues. They
also can clog more easily in small blood vessels, and break into pieces that disrupt
blood flow.
– Sickle cell anemia is inherited from both parents (recessive genetic disorder)
– most common in people of African and Mediterranean descent.
Symptoms
– usually don't occur until after age 4 months.
– Almost all patients with sickle cell anemia have painful episodes (crises), which
can last from hours to days. These crises can affect the bones of the back, the long
bones, and the chest; severe enough for hospital stay
– Delayed growth and puberty
– Fatigue
– Fever
– Jaundice, paleness
– Rapid heart rate
Normal RBC
•
•
Sickle Cell
Treatment
– need ongoing treatment, even when they are not having a painful crisis
– take supplements of folic acid (essential for producing red blood cells) because red blood
cells are turned over so quickly.
– manage and control symptoms, limit the frequency of crises.
– Painful episodes are treated with pain medicines and by drinking plenty of fluids. Nonnarcotic medications may be effective, but some patients will need narcotics.
– Blood transfusions are used to treat a sickle cell crisis. They may also be used on a regular
basis to help prevent strokes.
– Bone marrow transplants can cure sickle cell anemia.
Prognosis
– In the past, sickle-cell patients often died from organ failure between ages 20 and 40.
Today patients can live into their 50s or beyond.
– Causes of death include organ failure and infection. Some people with the disease
experience minor, brief, infrequent episodes. Others experience severe, long-term,
frequent episodes with many complications.