Science 30 Circulation and Immunity

Science 30Circulation and Immunity

Introduction: Launch Lab – Watching Blood Flow

•Procedure:▫Watch the video clip

showing blood circulation in the tail of a gold fish.

▫Answer the analysis questions.

Circulation in a Goldfish Tail

Structures of the Circulatory System•The circulatory system is the transportation system of the body.

•3 Main Functions1. Transports gases2. Regulates internal

temperature3. Protect against blood

loss and infection

Major Components•3 Major Components:

1. The heart – an organ that pushes blood through the body with its pumping action.

2. The blood vessels – serve as the “roadways” through which the blood moves.

3. The blood – carries nutrients, oxygen, carbon dioxide, water, wastes and many other materials throughout the body.

The Cardiovascular System•Together the heart and the blood vessels are known as the cardiovascular system.

The Structure of the Heart•Located on the left side of the chest

•The heart:▫Pumps blood▫Separates oxygen rich and poor blood

▫Keeps blood flow in one direction

•The walls of the heart are made up of cardiac muscle tissue

•The contractions of the cardiac muscle tissues are rhythmical and involuntary

•The human heart has 4 chambers:▫Left and right atria – fill with blood from body or lungs

▫Left and right ventricles – pump blood to the body or lungs

•The left and right side is separated by a thick wall called the septum

Blood Flow through the Heart•Oxygen-poor blood enters the heart from the vena cava

•Superior vena cava collects blood from upper body

•Inferior vena cava collects blood from below the chest

•vena cava R atrium R ventricle pulmonary arteries lungs L atrium L ventricle aorta body

Valves of the Heart•4 valves control direction of flow:

•Right atrioventricular valve:▫Separates right atrium and ventricle

▫Tricuspid; made of 3 flaps•Left atrioventricular valve:

▫Separates left atrium and ventricle

▫Bicuspid; made of 2 flaps

•Chordae tendinae:▫hold atrioventricular valves in place▫prevent valves from being pushed back into atria

•Semilunar valves control the flow of blood into the aorta and pulmonary artery

• Using blue and red pencils or pens, diagram the pathway of blood through the heart using arrows. Use blue to represent deoxygenated blood and red for oxygenated blood.

• Blood enters the right atrium through the ________________.

• Blood flows from the right atrium into the right ventricle through the _________________.

• Blood is pumped from the right ventricle into the pulmonary trunk that splits into the right and left _____________________.

• Blood returns from the lungs by way of the right and left ____________________.

• Blood enters the ____________________ when it returns from the lungs.

• Blood flows past the ________________________ as it enters the left ventricle.

• The left ventricle pumps out past the ______________________ into the aorta.

The Structure of Blood Vessels•Three types of blood vessels:•Arteries:

▫carry oxygen-rich blood away from the heart

▫thick and highly elastic walls•Veins:

▫carry oxygen-poor blood towards the heart

▫thinner walls and large inner circumference

▫have one-way valves to prevent back flow

•Capillaries:▫network of fine vessels where gas and

nutrient transfer to tissues occurs. Capillaries join arteries to veins

▫Capillary walls are a single cell thick

1. Label the diagram2. Use blue and red to indicate whether the

vessel carries oxygenated blood (red), deoxygenated blood (blue) or both.

3. Compare the structure and function of the three types of blood vessels.

Blood Vessel Type

Structure Description

Function

Artery

Vein

Capillary

The Beating Heart•The stimulus that triggers a heartbeat is an

electrical signal that originates from within the heart.

•The sinoatrial (SA) node is a bundle of specialized muscle tissue that stimulates the muscle cells to contract and relax rhythmically

•Located in the wall of the right atrium

•SA node is also called the “pacemaker” because it sets the pace for cardiac activity

•The SA node generates an electrical signal that spreads over the two atria simultaneously.

•As the atria contract, the signal reaches the atrioventricular (AV) node.

•The AV node transmits the electrical signal through the bundle of specialized fibres called the bundle of His.

•The bundle of His relays the signal through two bundle branches that divide into fast-conducting Purkinje fibres

•Purkinje fibres initiate the simultaneous contraction of all cells of the right and left ventriclesHeartbeat signal

ECG•Changes in voltage of the heart can be

measured using an electrocardiogram (ECG)•An ECG measures the electrical activity of

the heart as it contracts and relaxes•Irregular spikes or changes in the spacing of

waves can be used to diagnose different heart conditions

Blood Pressure•Blood passing through vessels exerts

pressure against vessel walls, called blood pressure

•Changes in blood pressure corresponds to phases of the heartbeat

•Maximum pressure is called systolic pressure, during ventricle contraction

•Lowest pressure is called diastolic pressure, occurs just before the ventricles contract

•Sphygmomanometer (blood pressure cuff) measures blood pressure

Cardiac Output and Stroke Volume•Cardiac output is the amount of blood

pumped by the heart, measured in mL/min•Cardiac output is an indicator of the level

of oxygen delivered to the body and the amount of work the body’s muscles can perform

•Heart rate is the number of heartbeats per minute

•Stroke volume is the amount of blood forced out of the heart with each heartbeat.

•cardiac output = heart rate x stroke volume

•Stroke volume depends on:▫How easily the heart fills with blood, related

to “stretchiness” of ventricular walls and volume returning to heart from veins

▫How readily the heart empties, related to the strength of the ventricular contraction

•Average person has a stroke volume of 7o mL and a resting heart rate of 70 beats/min

•Cardiac output = 70 mL x 70 beats/min = 4900 mL/min

•Average person has 5 L of blood in their body; the total volume of blood circulates through the heart about once every minute.

Pathways of the Circulatory System•The circulatory system has 3 pathways:▫Pulmonary pathway – transports blood between the heart and the lungs

▫Systemic pathway – moves blood from the left ventricle to the tissues and back to the right atrium

▫Coronary pathway – provides blood to the heart itself

Tracing the Pathways…•Tracing the pathway of blood beginning in right atrium…

pulmonary pulmonary systemic systemic

(to lungs) (to heart) (to tissues) (to heart)

Tracing the pathway of blood through coronary…▫Heart does not use blood inside chambers to get nutrients/ remove wastes; walls are too thick for diffusion

▫The heart is covered in a network of vessels

▫Oxygenated blood is supplied from the coronary artery coming off of the aorta

▫Deoxygenated blood enters the right ventricle before heading to the lungs.

Cardiovascular Disorders and Treatments•Cardiovascular disease is the leading cause of death for Canadians

•Can be reduced with lifestyle changes:▫not smoking▫Eating healthy diet▫Exercising

•Atherosclerosis:▫thickening of artery walls▫Elastic properties diminished

•Atherosclerosis:▫Build-up of fatty deposits on wall of artery▫Blood flow is decreased, blood pressure is

increased▫Especially dangerous in arteries of heart,

neck, brain, legs, kidneys▫Treated with aspirin to

prevent platelets from sticking together (clots)

▫Treated with medication to breakdown existing clots

Artherosclerosis

•Surgical treatments such as angioplasty; permanent stent is inserted into artery to “re-open” passage way

Angioplasty

•Coronary bypass operation – healthy vessels are taken from elsewhere in the body and used to create a new pathway around a blocked vessel.

Coronary Bypass Surgery

Congenital Heart Defects•Some heart defects are congenital, they are present since birth

•Common congenital defects:▫walls dividing chambers

▫valves of the heart▫structure of the blood vessels near the heart

•Heart murmur – describes any misflow of blood through the heart▫Ie. One or more of the valves not opening properly

▫Valve defects can be heard with a stethoscope as a whooshing or rasping sound (caused by blood “leaking” through the valve

•Can be also be diagnosed with CT scan, CAT scan, MRI scan by creating a 3D image of the organBicuspid/ Mitral valve RegurgitationHeart Transplant

Components of Blood

Blood• Average 70kg person has 5L of

blood.• 55% of blood is fluid,45% is blood

cells.• Plasma = fluid; 90% water and

10% proteins, vitamins, glucose...• There are 3 groups of proteins in

plasma:1. Albumins: draws water back into

capillaries2. Globulins: produces antibodies 3. Fibrinogens: used to clot blood.

A. Red Blood cells (erythrocytes)

•Make up 99% of blood cells.•Main function = transport oxygen (each rbc can have 4 oxygen molecules).

•Respiratory pigment hemoglobin allows rbc’s to carry oxygen ( 70x more than without hemoglobin)- gives red color!

•Without hemoglobin, life can be maintained for 4.5s; with = 5 minutes.

•biconcave shape to maximize SA for gas exchange.•Enucleated = no nucleus when mature, allows for more oxygen to be carried. Bone marrow produces rbc’s, can not reproduce without a nucleus.

Bone marrow•Erythropoiesis = rbc production ( occurs in bone marrow).

•Rbc’s begin as stem cells, divide and shrink- losing nucleus.

• Age of rbc’s is monitored by wbc’s; when rbc is 120 days, it releases hemoglobin and is transported from the cell.

•Iron (globin) is recycled and used in new rbc’s; heme is converted into bile pigments (bilirubin).

B. White blood cells (Leukocytes)•Around 1% of blood.•Responsible for:

housekeeping/ defence.•Have a nucleus.•Made in bone marrow; last

13- 20 days.•Destroy invaders by:

▫Phagocytosis: move towards microbe. Enzymes released digest leukocyte and microbe; fragments = pus.

C. Platelets (thrombocytes)•Have no nucleus.•Produced in bone marrow; last 5-9 days.•Irregularly shaped, very fragile and responsible for blood-clotting reactions.

blood

D. Blood Clotting•Maintains homeostasis.•Platelets break when striking a sharp object .

•Fibrinogen breaks up into fibrin threads. These seal the cut: prevent bacteria from entering and create a framework for wbc’s to patch up cut.

•A thrombus is a blood clot that seals the vessel = blocks vessel and prevents gas exchange.

•2 types:▫Cerebral: clot in brain, causes a stroke.▫Coronary: clot in artery, causes heart

attack.•Embolus = dislodged blood clot, travels to other organs; life threatening

HemophiliaThe ability to produce fibrinogen to form a clot is hindered.Czar Nicholas II son had hemophilia.

Blood DonationInitial Reception Area:•Contact and previous donation information is confirmed

•An RN tests blood for hemoglobin levels▫139 g/L

Donor Screening:•Questions related to general health are answered by donor.

•Donor looks over required reading materials prior to entering screening booth.

Private Screening Area•RN tests:

▫heart rate: 74 beats/min▫blood pressure: 118/72

mmHg▫temperature: 36.6 °C

•RN asks series of questions related to lifestyle choices that may put donor at risk of infection for blood-borne pathogens

The Collection Process•The RN uses a sphygmomanometer to locate a prominent vein on inner elbow

•Once needle is inserted in vein vials of blood are collected for testing

•Pressure is fully released from sphygmomanometer and full blood flow returns

•500 mL of blood is collected▫6 min and 30 sec

•Donor waits a minimum of 2 minutes following donation to ensure proper clotting in vein

•Whole blood will be separated into RBCs, plasma and platelets

How It’s Made: Blood Donation

How Much Blood Does it Take?Different medical procedures require varying amounts of blood. For example:

Coronary Artery Bypass: 1-5 unitsFractured Hip/Joint Replacement: 2-5 unitsCardiovascular Surgery: 2-25 unitsBleeding Ulcer: 3-30 unitsBrain Surgery: 4-10 unitsAuto Accident/Gunshot wound: up to 50 unitsLiver Transplant: up to 100 unitsOther Organ Transplants: up to 10 unitsBone Marrow Transplant: up to 2 units per daySickle Cell: up to 4 units per monthAplastic Anemia: up to 4 units per monthCancer: up to 8 units per week

The Immune Response

The Defence System•The human body defends itself against the constant attack of pathogens.▫Protozoans (parasites): ie. Malaria▫Fungi (molds): ie. Athlete’s foot▫Viruses: infect host cell and reproduce genetic material. (ie. influenza, HIV)

▫Bacteria: rapidly reproduce, killed with anibiotics. (ie. E. coli, samonella)

BrainPOP - Viruses

•Pathogens are prevented from entering the body, or are destroyed once inside.

•3 lines of defense:▫Barriers▫General/ non-specific ▫Specific

BrainPOP – Immune System

Barriers:•physical or chemical

•Examples: eyelashes, cilia, tears, stomach acid, skin

•Skin is the largest barrier

Non-Specific Defences (cell-mediated):•Involves 3 types of white blood cells:▫Macrophages, neutrophils & monocytes kill pathogens via phagocytosis

▫Also kill cancerous or infected body cells

Specific Defences (antibody-mediated):•The third line of defence is immunity

•Immunity is developed by the specific defenses, using antibodies

•Your body “catalogues” the molecules that are present in your body to recognize antigens that are present on the “self” cells. Antigens:▫proteins that are present on the surface of cells

▫function as an identification system

•Antigen receptors on T cells and B cells allow them to recognize foreign antigens and respond

•Antibodies are proteins that recognize foreign substances and act to neutralize or destroy them.

•Individuals develop unique immunity due to genetics and exposure to foreign substances over time.

•Antibodies have the same shape as the antigen receptor for a specific antigen.

•Most antibodies are specific and can bind to only one type of antigen.

•The specific immune system is primarily due to the lymphocytes in the circulatory system:▫B-cells – formed and mature in bone marrow: plasma B-cells, memory B-cells

▫T-cells – formed in bone marrow and mature in the thymus gland: helper T-cells, killer T-cells, memory T-cells, suppressor T-cells

B-cells•Each B-cell produces a specific antibody

•Plasma B-cells can rapidly produce antibodies

•B-cells recognize foreign invader’s antigens1. Antibodies attach to invading

antigens to disable or kill2. Memory B-cells remain in blood

after infection; immediately produce antibodies if antigen is detected in future

T-cells1. Helper T-cells: identify antigens and

communicate with plasma B-cells2. Killer T-cells: target damaged body cells

(ie. cancerous cells)3. Suppressor T-cells: once invader is

destroyed, signal end of immune response

4. Memory T-cells: remain in the blood following infection, allow for quick response if antigen is detected in the future

Vaccinations•Memory B-cells and T-cells can provide immunity to viruses; you don’t get sick from the same one twice.

•Vaccinations are a dead/weakened strain of the virus injected, antibodies are produced and immunity is created.

BrainPOP – Flu and Flu Vaccine

Immune System Disorders•Autoimmune disorder –T cells or antibodies mistakenly attack body’s own “self” cells.

•Exact cause for confusion is not known

•Tendency to inherit condition•Condition most often begins after recovery from an infection

Rheumatoid arthritis:•chronic autoimmune disorder•characterized by an inflammation of the joints•immune system attacks joints•symptoms: pain, stiffness, swelling, fever, and fatigue

•can cause permanent disability•Treated with immune suppressing drugs

Rheumatoid Arthritis

Allergies•An allergy is an exaggerated immune response to a harmless material

•Two types of reactions:▫Immediate▫Delayed

BrainPOP - Allergies

Immediate Allergic Reaction:•Most common•occurs within seconds of contact•antibodies trigger cells to release histamines

•Histamines cause areas to swell•triggers release of cellular fluids•Some forms of asthma are an immediate allergic reaction

Delayed Allergic Response•set off by T cells that have been sensitized by previous contact with allergens.

•Reaction may be immediate (runny nose) or delayed (wheezing, aches and pains)

•A severe immediate response is called anaphylaxis

•An EpiPen (dose of adrenaline) counteracts the allergic response