1. The Circulatory System

2. Functions of the Circulatory system
Transportation of water, Oxygen, CO2
Distribution of nutrients
Maintenance of body temp
Circulation of hormones

3. BLOOD = 5 L (8% of body weight) Constituents of blood Plasma
Average amount of blood in a human body (70kg)
= 5 L (8% of body weight)
Constituents of blood
Plasma
Erythrocytes (red blood cells)
Leucocytes (white blood cells)
Platelets
BLOOD

4. PLASMA Pale yellow liquid component of the blood
Contains - dissolved gases - nutrients - wastes - hormones (factor 8 for blood clotting) - RBC - WBC - Platelets

5. Red Blood cells (Erythrocytes)
No Nucleus!
Responsible for transporting O2 and CO2
Contains haemoglobin molecules that allow the bonding of oxygen to the cells to occur
(with haemoglobin, blood can carry enough O2 to support life for around 5 mins, without Haemoglobin the blood could support around 5 seconds of life)

6. White Blood cells (Leucocytes)
Protect the body against disease
Much fewer in numbers than RBC
Several Types (all contain nucleus)
-Some engulf foreign particles, -Some produce anti bodies and form the basis of the immune system.

7. Platelets
Small fragments of bone marrow Primary function is to assist in the clotting of blood

8. Chemical Composition of blood (per 1L)

9. Blood in centrifuge

10. TASK BLOOD CONSTITUENTS
Summary of red blood cells, white blood cells, plasma and platelets
THE CIRCULATORY SYSTEM
Draw Diagram of the heart labelling all chambers, valves, arteries and veins
Questions from ‘Nature of Biology’ Chapter 6
1-5, 8,9,10

11. THE CARDIO VASCULAR SYSTEM

12. TYPES OF CIRCULATION OPEN vs CLOSED
OPEN: e.g. Fish, insects, arachnids
Some animals do not have specialised fluid such as blood for transport, rather they use the fluid in between cells called Interstitial fluid
This is known as an Open circulatory system
There is still the presence of a heart in organisms with an open circulatory system
This fluid is used to carry everything from CO2, O2 – carbohydrates and Hormones CLOSED: e.g. Mammals, Marsupials, etc (see next slides)

13. Chambers of the heart

14. THE HEART AND THE FLOW OF BLOOD
FOUR CHAMBERS: 2 atrium (top), 2 ventricles (bottom)
FUNCTION: The heart pushes blood around the body by its chambers contracting and forcing blood into the next chamber
The blood needs to be pumped between the lungs and the cells of the body to carry O2 to the cells, and CO2 back to the lungs
Backflow of blood is stopped by the valves
FOUR MAJOR VALVES
Tricuspid valve between R ventricle and R atrium
Mitral valve between the L Atrium and L Ventricle
Pulmonary valve between R Ventricle and the Pulmonary artery
Aortic Valve between the L ventricle and the Aorta

15. Blood flow through the heart

16. OXYGENATED BLOOD
Flow of blood: (From the body) Superior / Inferior Vena cava , Right Atrium, Right Ventricle, Pulmonary Artery,
LUNGS
Pulmonary Vein, Left Atrium, Left Ventricle, Aorta (To the body)
Gives CO2 to lungs
Collects O2 from lungs

17. Cardiovascular system

18. THE BLOOD VESSELS Arteries Heart cell
Arteries: Carry blood away from the heart (oxygenated)
Arterioles: Small arteries
Capillaries: small veins, extend circulatory network right in between cells
Veins: Carry blood to the heart (de-oxygenated)
Capillaries
Arteries
Arterioles
Heart
cell
Veins

19. STRUCTURE OF ARTERIES
Arteries are more muscular and thicker than veins, this is because they swell as each wave of blood is ejected from the heart. They then recoil to propel elastically to push blood further on
STRUCTURE OF VEINS
The Lumen of a vein is much larger than that of an artery. (over 60% of blood is distributed in the veins as a reservoir, should extra volume be required (exercise)
Veins have valves to help prevent backflow
Veins rely on the contraction of skeletal muscles to help propel blood back to the heart against gravity (draw diagram)

20. LUNG STRUCTURE
The lungs are basically a series of air sacs that fill with air due to the pressure difference inside the lungs and outside the body The air travels through a series of passages Trachea Bronchus Bronchioles Alveoli (point of diffusion)

21. GAS EXCHANGE IN MAMMALS
One of the main functions of the blood is to carry O2 to the cells and CO2 back to the lungs to be expelled
This is achieved via diffusion occurring in the Alveoli in the lungs (see below)
Blood pathways carry blood past the alveoli were there is a very thin membranous surface where the CO2 can diffuse out of the RBC and into the alveoli sacs, and O2 Diffuses from the alveoli sacs into the RBC
CONDITIONS REQUIRED FOR DIFFUSION
Surface must be moist (gases dissolve in an out by dissolving into water)
Must be a thin permeable membrane
Must have a concentration gradient allowing passive diffusion

22. CELL PERFORMANCE To function the cells require O2 for respiration
The more O2 cells get, the harder they can work (e.g. high intensity exercise)
Very fit athletes can posses several factors that increase the levels of respiration they can undertake
Large lungs to take in large amounts of CO2
High diffusion efficiency between the lungs and blood
High O2 carrying capacity in the blood (high RBC + hemoglobin count)

23. TASK The Respiratory System
Questions from ‘Nature of Biology’ Chapter 6
11-14, 16
Chapter 6 Review Questions – P171
1, 3,5,6,7,14