The problem

How do we get nutrients and gases to every cell of the body?

The Circulatory System

What is the circulatory system?

What are its functions?

Circulatory system - structure Consists of

Blood – the medium The Heart – the pump Blood Vessels – the pathways

Function

Transports substances within the body Nutrients/waste products Gases – oxygen/carbon dioxide Hormones Immune system

Also assists with temperature regulation

Blood

Plasma Makes up 55% of blood volume

90% water 7% plasma protein

Fibrinogen, albumins and globulins – assist in transport and clotting

2% dissolved solutes Nutrients, wastes, hormones

1% dissolved salts Sodium, calcium, potassium, and magnesium chloride, bicarbonate, phosphate and sulfate

Formed elements

Formed Elements

Erythrocytes (gk Erythro = red) Red blood cells Carry oxygen

Leukocytes (gk Leuco = white) White blood cells Immune system - defence

Platelets Clotting

Red Blood Cells

Red Blood Cells

aka erythrocytes Carry oxygen and carbon dioxide Biconcave Do not have a nucleus Produced in bone marrow and stored in the

spleen Contain hemoglobin – the protein which carries

oxygen and carbon dioxide

Hemoglobin

Hemoglobin

Hemoglobin

Each hemoglobin has 4 subunits Each subunit has an iron atom which

associates with one oxygen/carbon dioxide molecule

A shortage of hemoglobin is called anemia

White Blood Cells

Part of the immune system Defends the body against invaders Pus can form when there is an infection

A mixture of living and dead white blood cells and bacteria

Responds to infection by: Enveloping foreign bodies Destroying infected cells Signalling the body – inflammation, fever

Platelets

Platelets

Contain the protein fibrinogen Responsible for clotting

Blood Types

What are they? How are they determined?

Blood types

The four blood types are A, B, AB and O. They are determined by the presence (or

absence) of the A and B antigens on the cell A separate antigen (Rh factor) determines

whether or not it is positive or negative

Donating Blood

Recipient

Donor

A B AB O

A

B

AB

yes

yes

yes

yes

O

yes

yes

yes

yesyes

no

no

no

no

no

no no

The Heart

Inferior Vena Cava

Right Ventricle

Right Atrium

Pulmonary Veins (right)

Pulmonary Artery (right)

Superior Vena Cava

Aorta

Pulmonary Artery (left)

Pulmonary Vein (left)

Left Atrium

Left Ventricle

Septum

Semi-lunar Valve[pulmonary]

Semi-lunar Vavle[aortic]

Atrioventricular (A-V) Valve[tricuspid]

Atrioventricular (A-V) Valve[bicuspid/Mitral]

Arteries

The Heart

Muscled organ used to pump blood Consists of 4 chambers Two types of chambers – atria and ventricles Heart can be divided into left and right sides

Septum – tissue that separates left and right sides

Atria and Ventricles

Two types of chambers Atria

Receive blood Ventricles

Pump blood

Left and Right Sides

Left side Receives deoxygenated blood from body Pumps it to lungs

Right side Receives oxygenated blood from lungs Pumps it to the body

Two loops

Vena cava

Right atrium

Right Ventricle

Pulmonary arteries

Lungs/capillaries/alveoli

Pulmonary Veins

Left atrium

Left Ventricle

Aorta

arteries

arterioles

capillaries

venules

veins

Systemic and Pulmonary Circuits Blood travels along two distinct pathways SYSTEMIC CIRCUIT

From the heart to all the tissues and back Leaving the heart with oxygenated blood and

returning with deoxygenated blood PULMONARY CIRCUIT

From the heart to the lungs and back Leaving the heart with deoxygenated blood and

returning with oxygenated blood

Blood Vessels

Blood Vessels

Arteries – carry blood away from the heart Veins – carry blood towards heart Capillaries – site of diffusion

Arteries

Arteries

Carry blood away from the heart Thick, muscular walls – epithelial, muscle

and connective tissue Elastic Found deep within muscle tissue Blood propelled by heart, blood pressure Arteries branch into smaller arterioles

Veins

Veins

Carry blood towards the heart Thin, elastic walls Found near the surface of the skin Contain valves to ensure blood only flows in

one direction Blood is propelled by muscular contraction Smaller veins called venules collect blood

from capillaries

Capillaries

Capillaries

Site of nutrient exchange/diffusion Extremely narrow – only one red blood cell

may pass at a time Extremely thin walls Beds of extremely dense, diffuse blood

vessels provide surface area for diffusion

Blood Pressure

The force of the blood on the walls of the blood vessels

Systolic – while the heart is contracting Diastolic – while the heart is relaxing

Measuring Blood Pressure

Measured with a SPHYGMOMANOMETER and a stethoscope

Measuring blood pressure

Systolic Pressure

Diastolic Pressure

Cuff Pressure

No pulseCuff cuts off circulation

PulseSystolic pressure ableto overcome cuff pressure

No pulseBoth systolic and diastolicpressures are greater thanCuff pressure. Blood flows smoothly

Measuring Blood Pressure

Inflate cuff until circulation cut off Slowly release pressure Listen Pulse is heard when systolic pressure is

reached Pulse stops when diastolic pressure is

reached

Blood Pressure

A normal systolic pressure is 120 mm Hg A normal diastolic pressure is 80 mm Hg

Blood Pressure

What is your blood pressure? What factors do you think affect blood

pressure? Design and conduct an experiment to

determine one of the factors affecting blood pressure.