Blood Function

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, 000 per microlitre– 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, veins,

capillaries• 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

Coronary Arteries • Supply blood to the heart• Coronary Artery Disease– Plaque buildup causes

blockage in arteries• Lead to– Heart attack, stroke 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

• Diastole (dub)– Relaxation of heart

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