blood function
Post on 13-Feb-2016
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Blood Function• Connective Tissue– Transports dissolved gases (O₂, CO₂)
nutrients (glucose, amino acids, vitamins, minerals, enzymes, hormones, metabolic wastes, fatty acids, glycerol
• Regulates– pH – blood remains in the range of
6.8 – 7.4– Helps stabilize body temperature
• Maintains fluid volume– Removes excess salt
• Defense against pathogens and toxins
• Blood clotting– Prevent blood loss
Blood Composition
• The average person has about 5 litres of blood
Cellular Components of blood
RBC’s (Erythrocytes)• Most abundant cell• Biconcave shape• Red blood cells are produced in
bone marrow– Controlled by hormone called
erythropoietin• Have no nucleus• Contain hemoglobin– Transports oxygen and carbon
dioxide• Survive approx 120 days
WBC’s (Leukocytes)• Protect the body from infection• Neutrophil (first responders)– Defend against bacterial or fungal infection– Form pus
• Eosinophil – Defend against parasitic infection
• Basophil– Allergic response– Release histamine
• Lymphotcyte– Specific immune response– Defend against virus, cancer
• Monocyte (Macrophage) – Phagocytosis
Platelets (Thrombocytes)• Small disk shaped clear
cell fragments• Survive 5-9 days • Form blood clots – Fibrinogen –protein that
promotes coagulation of platelets
Blood Cell Formation• RBC’s, WBC’s and platelets are all produced in the
bone marrow• WBC’s are stored in the spleen, thymus, lymph nodes • Platelets are stored in the spleen
Complete Blood Count (CBC)• Blood test done that is part of a routine medical assessment• It can test and monitor different diseases• Hb – hemoglobin • HCT – hematocrit - % of red blood cells in relation to blood
volume • K/uL – thousand per microliter
RBC Disorders• Anemia
– Low number of red blood cells – Symptoms: fatigue, pale skin,
shortness of breath– Treatment: transfusion, marrow
transplant• Iron-deficiency anemia
– Low iron intake– Treatment: iron pills, blood
transfusion • Sickle cell anemia
– Genetic condition, red blood cells change shape block blood flow
– Symptoms: severe pain, organ damage – Treatment: oxygen therapy, antibiotics
WBC Disorders• Leukemia– Cancer of the blood or bone marrow – Signs: Excessive build up of WBC’s,
infection, pneumonia– Symptoms: feeling sick, flu-like – Treatment: pharmaceutical
medication, radiation• Myeloma– Malignant tumor of bone marrow– Symptoms: Bone pain, weakness,
fatigue, weight loss, kidney problems– Treatment: radiation, steroids, stem
cell transplant
Platelet Disorder• Thrombocytopenia– Decrease in platelet count – 50 K/µL– Symptoms: bruising, nosebleeds, bleeding gums– Treatments: Corticosteroids, lithium carbonate
What Determines Blood Type • Antigen (type A and B)– Protein molecules called
agglutinogens attach to the surface of red blood cells
• ABO Classification System – Presence or absence of antigen – 4 different types of blood
• Rh Protein– Surface protein (ion channel)– Positive or Negative – Ex; A positive (A+)
Blood Type is Genetic • A and B antigen proteins are produced by two
different enzymes that are encoded by two different alleles of the same gene
• O allele codes for protein that is not functional • Possible combinations:
Blood Transfusions • Donor and Recipient blood
types need to match• Surface molecules on
blood need to be the same • Otherwise antibodies will
recognize blood as foreign triggering an immune response
• Result in blood clotting
Donating Blood
• O+ (39% of Canadians share your blood type)– Most common blood type in Canada – Given to all other positive blood types (O+, A+, B+, AB+)
• O- (7% of Canadians share your blood type)– Universal Donor – compatible with all blood types
• A+ (36% of Canadians share your blood type)– Receive blood from (A+, A-, O+, O-)
• A- (6% of Canadians share your blood type)– Receive blood from (A-, O-)
• B+ (7.6% of Canadians share your blood type)– Receive blood from (B+, B-, O+, O-)
• B- (1.4% of Canadians share your blood type)– Receive blood from (B-, O-)
• AB+ (2.5% of Canadians share your blood type)– Universal recipient – receive blood from any type
• AB- (0.5% of Canadians share your blood type)– Universal donor for plasma– AB+, AB- are Universal donors for plasma
Cardiovascular System• Blood vessels– Arteries,
arterioles, capillaries, venules, veins
• Heart– Composed of
cardiac muscle tissue
– Pumps the blood throughout the body
Cardiovascular System • Pulmonary Circuit (lungs)– Moves blood from the heart to the lungs and back to the
heart– Blood moving from the heart to the lungs is de-oxygenated – Blood moving from the lungs to the heart is oxygenated– Carbon dioxide is being delivered, oxygen is being picked up
• Pulmonary arteries/veins carry blood
Cardiovascular System• Systemic Circuit– Movement of blood from
heart to the body and back to the heart
– Blood moving from heart to the body is oxygenated
– Blood moving from the body back to the heart is de-oxygenated
– Oxygen is being delivered, Carbon dioxide is being picked up
Blood Vessels • Arteries– carry blood away from the
heart• Arterioles– Branches out from artery and
leads to capillaries• Capillaries– Smallest blood vessel– capillary bed supplies organ
with blood• Veins – Carry blood to the heart– Contain valves to stop
backflow• Venules– Carry blood from capillary bed
to vein
The Heart • Four chambers– Left/Right Ventricles - pump
blood to the body – Left/Right Atria – receive
blood from the body• Muscle tissue– Septum – separates
oxygenated blood from deoxygenated blood
• Valves– Four valves – keep the blood
flowing in one direction • Nodes– AV/SA nodes - pacemaker
Path of Blood Through the Heart• Draw a flow chart
showing the path of blood through the heart
• Starting point– Body– deoxygenated
blood• End Point– Body – oxygenated blood
Path of Blood Through the Heart
• Superior/Inferior Vena Cava→ Right Atrium→ Tricuspid Valve→ Right Ventricle→ Pulmonary Valve→ Pulmonary Artery→ Lungs → Pulmonary Veins→ Left Atrium→ Mitral Valve→ Left Ventricle→ Aortic Valve→ Aorta→ Body
Coronary Arteries • Supply blood to the heart• Coronary Artery Disease– Plaque buildup causes
blockage in arteries• Lead to– Heart attack, ischemia
• Causes– Smoking, hypertension, high
cholesterol, diabetes, diet, obesity
• Treatment– Angioplasty procedure– Coronary artery bypass graft
The Cardiac Cycle • All of the events
that occur during one heart beat
• Systole (lub)– Contraction of
heart (leaving chambers)
• Diastole (dub)– Relaxation of
heart (filling chambers)
Cardiac Cycle (Diastole)• Ventricles relaxed• Blood flowing from LA and RA
into LV and RV• Blood flows through
atrioventricular valves (mitral/tricuspid)
• Aortic/pulmonic valves closed• RA receives venous blood from
body through superior/inferior vena cava
• LA receives oxygenated blood from lungs via pulmonary veins
• Diastole ends, both atria contract
Cardiac Cycle (Systole)• Ventricles contract• Aortic and pulmonic valves
open • Blood ejected into aorta
and pulmonary arteries• Atrioventricular valves
closed during systole • Atria fill with blood via
vena cava and pulmonary veins
Cardiac Output (CO)• Volume of blood
ejected from the left or right ventricle into the aorta or pulmonary trunk per minute
• Depends on– Heart rate – Stroke volume
Cardiac Output = (HR bpm)(SV L/beat)
Stroke Volume (SV)• Amount of blood pumped by
each ventricle with each heartbeat
• Average person pumps 70 ml (0.07L) per beat at rest
Stroke Volume = EDV – ESV• End Systolic Volume – Amount of blood ejected during
systole – 50mL remain
• End Diastolic Volume– Amount of blood filling during
diastole– Each ventricle contains 120mL at
the end of diastole
Cardiac Output Per Min • Calculate the total volume of blood (L) that travels
through the heart per minute (L/min) • EDV = 120 mL• ESV = 5 mL• SV = ?• CO = ?• HR = 70 bpm
Arrythmia• Irregular heartbeat– Tachycardia – too fast (over 100 bpm)– Bradycardia – too slow (less than 60
bpm)– Premature – too early– Fibrillation – irregularly
• Can occur in the atrium or ventricles
• Causes– Smoking, alcohol, drugs, caffeine,
heart disease, hypertension, hyperthyroidism, heart attack, diabetes, old age, obesity
Blood Pressure• Arteries change shape in
response to blood pressure
• Systolic Pressure – Pressure on the walls of
the arteries from ventricular contractions
– Normal is 120• Diastolic Pressure– Pressure on the walls of
the arteries when the heart is at rest
– Normal is 80
Hypertension• High Blood Pressure– 140/90 or higher
• Leads to (chronic)– Cardiac disease, kidney
disease, atherosclerosis, eye damage, stroke
• Causes– Alcohol, smoking,
obesity, caffeine, salt, stress, age, genetic
• Treatment – Diet, medication
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