The blood system continuously transports substances to cells and simultaneously collects waste products.

6.2 The Blood System

Essential idea:

6.2 The Blood System

Syllabus Reference

6.2 The Blood System

Syllabus Reference

6.2 The Blood System

Vocabulary

6.2 The Blood System Quizlet

6.2 The Blood System

What are the components of blood?

Starter

6.2 The Blood System

• Blood can be separated by centrifuging.
• You can count blood cells using a haemocytometer
• 1ml blood contains about;

5 - 6 million red blood cells

5 -10,000 white blood cells

250 - 400,000 platelets

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6.2 The Blood System

• No nucleus, biconcave
• In humans about 8µm
• Filled with haemoglobin (a red protein which binds with O₂)
• Short life span - 120 days
• Continuously replaced by cells in the bone marrow.
• Transport oxygen and (some) carbon dioxide

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6.2 The Blood System

Erythrocytes

• They are subdivided into

Phagocytes - engulf bacteria

Lymphocytes - produce antibodies

Basophils - secrete histamines

Eosinophils - cause allergic reactions

• They are involved in defence against disease and immunity

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6.2 The Blood System

Leucocytes (Leukocytes)

Leucocytes

lymphocyte

phagocyte

6.2 The Blood System

• Large, flexible cells
• Lobed nuclei
• Squeeze through capillary walls to sites of infection
• Dead phagocytes = pus!

6.2 The Blood System

Phagocytes

• Large nucleus
• Many copies of gene for antibody production
• Produce antibodies

6.2 The Blood System

Lymphocytes

• Fragments of cells broken from large cells in the bone marrow
• Function is to aid the process of blood clotting

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6.2 The Blood System

Platelets

• Straw coloured
• Mainly water with dissolved substances in it
• It is the main transport medium in the body; chemicals and heat from hot regions regions to cooler ones
• Plasma proteins are involved in buffering and defence against injury and disease

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6.2 The Blood System

Plasma

Blood Smear

erythrocytes

platelets

phagocyte

lymphocyte

6.2 The Blood System

6.2 The Blood System

6.2.7 State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat.

• Transport (nutrients, gases, hormones, antibodies, urea, heat)
• Homeostasis (hormones, negative feedback)
• Immune system (leucocytes & antibodies)
• Maintenance of body temperature
• Communication (hormones)

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6.2 The Blood System

Functions of Blood

Who was William Harvey?

6.2 The Blood System

Who was William Harvey?

6.2A1 William Harvey’s discovery of the circulation of the blood with the heart acting as the pump.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

6.2 The Blood System

Cross section of vein

6.2 The Blood System

arteries

capillaries

veins

arterioles

venules

6.2 The Blood System

6.2. U1 Arteries convey blood at high pressure from the ventricles to the tissues of the body.

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(Recoil)

(Doesn’t Burst)

(Maintain Pressure)

(Reduce Friction)

https://www.youtube.com/watch?v=4xG2aJa6UyY

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Thick Collagen Layer

Thick Muscle and Elastin Layer

Smooth

Narrow Lumen

1.

2.

3.

4.

6.2 The Blood System

6.2 U2. Arteries have muscle cells and elastic fibres in their walls.

Endothelium

Muscle Fibres

Elastic Fibres

Connective Tissue (Collagen)

Tunica Intima

Tunica Media

Tunica Adventitia

6.2 The Blood System

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

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(No Recoil)

(Low Pressures = Not going to burst)

(Build up blood to return to the heart)

(No Friction)

https://www.youtube.com/watch?v=4xG2aJa6UyY

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Thin Collagen Layer

Thin Muscle and Elastic Layer

Bumpy endothelium

Wide Lumen

1.

2.

3.

4.

Valves

5.

(prevent backflow)

6.2 The Blood System

6.2 U4 Valves in veins and the heart ensure circulation of blood by preventing backflow.

6.2 The Blood System

6.2 U4 Valves in veins and the heart ensure circulation of blood by preventing backflow.

6.2 The Blood System

Summary of blood vessels

6.2 S1. Identification of blood vessels as arteries, capillaries or veins from the structure of their walls.

• very thin walls
• only endothelium
• enhances exchange across capillary
• porous - allow phagocytes to squeeze through
• very narrow - width of one red blood cell - gives time for diffusion

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6.2 The Blood System

Capillaries: Built for exchange

6.2U4 Blood flows through tissues in capillaries. Capillaries have permeable walls that allow exchange of materials between cells in the tissue and the blood in the capillary

What can you identify?

A - aorta

B - right atrium

C - auricle

D - coronary arteries

E - myocardium

F - apex

6.2 The Blood System

External Features

6.2 S2Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.

There are 4 coronary arteries which supply the heart itself.

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2 at the front and 2 at the back

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coronary arteries

6.2 The Blood System

Coronary arteries supply heart muscle with oxygen and nutrients.

6.2 S2Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.

External View

FRONT

BACK

6.2 The Blood System

External View

6.2 S2Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.

6.2 The Blood System

6.2 S2Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.

6.2 The Blood System

6.2 S2Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.

Watch this!

6.2 The Blood System

6.2 S2Recognition of the chambers and valves of the heart and the blood vessels connected to it in dissected hearts or in diagrams of heart structure.

6.2 The Blood System

Left

Right

Right

Left

Atrium

Atrium

Ventricle

Ventricle

6.2 The Blood System

Vena Cava

Atrioventricular Valve (Tricuspid)

Pulmonary Artery

Lungs

6.2 The Blood System

Vena Cava

Atrioventricular Valve (Tricuspid)

Pulmonary Artery

Lungs

Pulmonary Valve (Semilunar)

Atrioventricular Valve (Bicuspid)

Pulmonary Vein

Aortic Valve (Semilunar)

Aorta

• The human circulatory system is a double circulatory system. It has two separate circuits and blood passes through the heart twice:
• the pulmonary circuit is between the heart and lungs
• the systemic circuit is between the heart and the other organs

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6.2 The Blood System

Define the term double circulation:

6.2 U7 There is a separate circulation for the lungs.

• Higher blood pressure is maintained
• There is separation of oxygenated and deoxygenated blood.
• High supply of oxygenated blood to different cells of the body.

6.2 The Blood System

Describe the advantages of this type of circulation:

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6.2 U7 There is a separate circulation for the lungs.

• Myogenic refers to a nervous impulse originating in muscle tissue itself.

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6.2 The Blood System

6.2 U8 The heart beat is initiated by a group of specialized muscle cells in the right atrium called the sinoatrial node.

6.2 U9 The sinoatrial node acts as a pacemaker.

https://www.youtube.com/watch?v=QflNbT23JCE

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Skeletal

Smooth

Cardiac

6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

intercalated discs with gap junctions and desmosomes

y shaped cardiac muscle cells

• Cardiac muscle tissue is a contractile tissue present only in the heart.
• It is striated in appearance, Involuntary, and myogenic (creates it’s own impulse)
• Shorter and wider than skeletal muscles, has one nucleus per cell
• Cell junctions fuse the plasma membranes of cardiac muscle cells (cells are Y shaped) and make them stick together.
• Communication junctions (intercalated discs) at some fusion points allow the cells to contract as a unit, i.e., when one cell receives a signal to contract, its neighbours are also stimulated to contract.
• Cardiac muscle cells have more mitochondria, as they are more reliant on aerobic respiration than skeletal muscle

6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

• Individual cells branch (Y shape) and join neighboring cells end-to end at junctions called intercalated disks which is a double membrane containing gap junctions and desmosomes

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6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

• Desmosomes are protein complexes that bind adjacent cells together allowing force generated in one cell to be transferred to the adjacent cell

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6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

• gap junctions are protein complexes that form pores between adjacent cells which electrically connect adjacent cells to one another as ions are able to pass freely between cells

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6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

• This allows for the rapid movement of ions and a low electrical resistance.

Vena Cava

Right Atrium

Left Atrium

Sinoatrial (SA) Node

Atrioventricular (AV) Node

Bundle of His

Purkinje Fibres

Bachmann’s Branch

6.2 The Blood System

D4.U1 Structure of cardiac muscle cells allows propagation of stimuli through the heart wall.

• The Sinoatrial Node (SA node) is a specialized myocardial structure that initiates the electrical impulses to stimulate contraction, and is found in the atrial wall of the right atrium.
• 60 – 100 cardiac contractions per minute

6.2 The Blood System

6.2 U8 The heart beat is initiated by a group of specialized muscle cells in the right atrium called the sinoatrial node.

6.2 U9 The sinoatrial node acts as a pacemaker.

Sinoatrial Node (SA Node)

Bachmann’s Branch

• The sinoatrial node sends out an electrical impulse that stimulates contraction of the myocardium (heart muscle tissue)
• This impulse directly causes the atria to contract and stimulates the AV node at the junction between the atrium and ventricle

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6.2 The Blood System

6.2 U8 The heart beat is initiated by a group of specialized muscle cells in the right atrium called the sinoatrial node.

6.2 U9 The sinoatrial node acts as a pacemaker.

• The Atrioventricular Node (AV node) delays the signal, to allow time for the ventricles to fill with blood.
• The AV Node sends signals down the septum via a nerve bundle (Bundle of His).

6.2 The Blood System

Atrioventricular Node (AV Node)

Bundle of His

6.2 U10 The sinoatrial node sends out an electrical signal that stimulates contraction as it is propagated through the walls of the atria and then the walls of the ventricles

• The contractions of the atria and ventricles must be staggered so blood flows in the correct direction.  When action potential is delayed about 0.12 seconds. Action potential starts at SA node and travels to the AV node.  The fibers in the AV node take longer to become excited. 

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• ​They have smaller diameter and don’t conduct as quickly, reduced number of Na+ channels in membranes, fewer gap junctions between cells, more non-conductive connective tissue in node.

6.2 The Blood System

D.4 U 3 There is a delay between the arrival and passing on of a stimulus at the atrioventricular node.

• Specialization in AV Node
• 1. S_____________ d____________ and do not conduct as quickly
• 2. R______________ # of ______ c_______________ in the membranes of AV Node cells
• a. G______________resting potential
• b. Prolonged r________________ period
• 3. F___________ g_______ j_____________ between cells of AV node
• 4. More n______-c___________________ tissue present

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smaller

diameter

reduced

Na⁺

channels

greater

refractory

Fewer gap junctions

Non-conductive

• The Bundle of His innervates nerve fibres (Purkinje fibres) in the ventricular wall, causing ventricular contraction

6.2 The Blood System

Purkinje Fibres

Bundle of His

6.2 U10 The sinoatrial node sends out an electrical signal that stimulates contraction as it is propagated through the walls of the atria and then the walls of the ventricles

6.2 The Blood System

D.4 U 5 ​Conducting fibres ensure coordinated contraction of the entire ventricle wall.

6.2 The Blood System

D.4 U 5 ​Conducting fibres ensure coordinated contraction of the entire ventricle wall.

6.2 The Blood System

D.4 U 5 ​Conducting fibres ensure coordinated contraction of the entire ventricle wall.

6.2 The Blood System

D.4 U 5 ​Conducting fibres ensure coordinated contraction of the entire ventricle wall.

• Relatively fewer myofibrils
• Bigger diameter
• Higher densities of voltage-gated sodium channels
• High numbers of mitochondria and high glycogen stores

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6.2 The Blood System

What are the adaptations of the Purkinje fibres?

Changes to blood pressure levels or CO₂ concentrations (and thereby blood pH) will trigger changes in heart rate

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6.2 The Blood System

6.2 U11 The heart rate can be increased or decreased by impulses brought to the heart through two nerves from the  medulla of the brain

Vagus Nerve (slows down)

Sympathetic (speeds up)

6.2 The Blood System

6.2 U11 The heart rate can be increased or decreased by impulses brought to the heart through two nerves from the  medulla of the brain.

6.2 U12 Epinephrine increases the heart rate to prepare for vigorous physical activity.

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Adrenaline (epinephrine)

Sympathetic Nerve

Vagus Nerve

a. sinoatrial node/SAN is a specialized group of muscle cells�OR

sinoatrial node/SAN is located in the right atrium ✔

b. acts as a pacemaker/controls the heart rate�OR

initiates/generates the heart beat/starts the cardiac cycle ✔

c. sends out electrical signal/impulses/depolarisations ✔

d. electrical signal stimulates contraction «of heart muscle» ✔

e. signal passes through walls of atria/passes to AV node ✔

f. then through walls of the ventricles ✔

g. medulla «oblongata of brain» can change/increase/decrease the rate ✔

h. through nerves/named example of nerve/autonomic/sympathetic/ parasympathetic nervous system ✔ In mph, only accept vagus nerve for slowing heart rate and sympathetic nerve for accelerating it.

1. one nerve increases the rate and the other decreases it ✔

j. epinephrine/adrenaline increases heart rate/force of contraction ✔

k. epinephrine/adrenaline prepares the body for vigorous activity/is part of fight or flight response ✔

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6.2 The Blood System

Explain the control mechanism of the heart rate. (7 Marks)

Checkpoint

v

• AV valve opens
• Blood moves into the ventricle
• AV Valve Closes
• Aortic Valve is closed
• Ventricle Pressure Increases

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6.2 The Blood System

6.2 A2 Pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle.

• @70% capacity AV Valve Closes to prevent backflow
• Aortic Valve is closed
• Ventricle Contracts
• Pressure Increases

• Aortic Valve opens
• Ventricle Contracts
• Pressure Increases as blood leaves the aorta
• Ventricle pressure drops

6.2 The Blood System

6.2 A2 Pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle.

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Partner up – 1 artist and 1 narrator

6.2 The Blood System

What are the pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle?

6.2 The Blood System

6.2 A2 Pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle.

6.2 The Blood System

6.2 A2 Pressure changes in the left atrium, left ventricle and aorta during the cardiac cycle.

1. Think for a minute or two about how you would explain the diagram on the worksheet. Run through the explanation in your head. Ask for any clarifications you need and make a note of answers.
2. Pair up with someone in the class for 5 minutes and take turns to say your explanation out loud. Offer suggestions of improvements to your partner.
3. Share your explanation with the whole class - at the whiteboard if you are confident enough.

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6.2 The Blood System

Think / Pair / Share

Checkpoint

There are 4 coronary arteries which supply the heart itself.

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2 at the front and 2 at the back

6.2 The Blood System

Causes and consequences of occlusion of the coronary arteries.

6.2A3 Causes and consequences of occlusion of the coronary arteries.

https://www.youtube.com/watch?v=3_PYnWVoUzM

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A coronary occlusion is the partial or complete obstruction of blood flow in a coronary artery

•The heart requires a lot of oxygen and nutrients

•Some oxygenated blood leaving the left ventricle goes directly to the heart through the coronary arteries.

•These branch many times to supply oxygen and nutrients throughout the cardiac muscle.

•When these get blocked a heart attack is likely and by-pass surgery required.

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This blockage is caused by a build-up of fats and is called a plaque.This condition is also known as atherosclerosis.

6.2 The Blood System

Causes and consequences of occlusion of the coronary arteries.

6.2A3 Causes and consequences of occlusion of the coronary arteries.

Coronary Occlusion

The image above is from an angiogram, it shows where the coronary arteries narrow as a result of atherosclerosis

6.2 The Blood System

Causes and consequences of occlusion of the coronary arteries.

6.2A3 Causes and consequences of occlusion of the coronary arteries.

• Atherosclerosis is a disease in which plaque builds up inside your arteries.
• Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows your arteries. This limits the flow of oxygen-rich blood to your organs and other parts of your body.
• Atherosclerosis can lead to serious problems, including heart attack, stroke, or even death.
• Chronic Kidney Disease, Peripheral Artery Disease and Carotid Artery Disease are conditions that can arise from Atherosclerosis

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6.2 The Blood System

Causes and consequences of occlusion of the coronary arteries.

6.2A3 Causes and consequences of occlusion of the coronary arteries.

Read more here: http://www.nhlbi.nih.gov/health/health-topics/topics/atherosclerosis/

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6.2 The Blood System

Causes and consequences of occlusion of the coronary arteries.

6.2A3 Causes and consequences of occlusion of the coronary arteries.

6.2 The Blood System

Checkpoint

6.2 The Blood System Quiz

6.2 The Blood System Kahoot

6.2 The Blood System

• Internal and external factors influence heart function.

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6.2 The Blood System

Essential Idea

• A normal heartbeat has two sounds, both caused by the closing of valves:
• Atrioventricular valves snap shut there is a “lub” sound
• Semilunar valve shut there is a “dub” sound

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6.2 The Blood System

State the cause of each of the two sounds of the heartbeat.​

D.4 U 6 Normal heart sounds are caused by the atrioventricular valves and semilunar valves closing causing changes in blood flow.

6.2 The Blood System

State the purpose of an artificial pacemaker device​

D.4 A 1 Use of artificial pacemakers to regulate the heart rate.

6.2 The Blood System

D.4 A 2 ​Use of defibrillation to treat life-threatening cardiac conditions.

6.2 The Blood System

6.2 The Blood System

• P wave
• simultaneous depolarization of both atria
• QRS Complex
• depolarization of both ventricles
• the repolarization both atria occurs at this time but is hidden by much larger ventricular depolarization
• T wave
• repolarization of both ventricles

6.2 The Blood System

State the purpose of an artificial pacemaker device​

D.4 A 1 Use of artificial pacemakers to regulate the heart rate.

D4.A2 Use of defibrillation to treat life-threatening cardiac conditions.