1. The Circulatory System
Chapter 33.1 & 33.2

2. Functions of the Circulatory System
The human body is made up of million of cells.
Most are not in direct contact with the external environment
This is why we need a circulatory system
The circulatory system transports oxygen, nutrients, and other substances thought out the body and removes waste from tissues

3. The Heart
Hollow
About the size of a fist
All muscle

4. The Heart
The walls of the heart are two thin layers of epithelial and connective tissue that sandwich around the muscle Myocardium
Powerful contractions of the myocardium pump blood through the circulatory system.

5. The adult heart contract 72 times per minute
The Heart
The adult heart contract 72 times per minute

6. The Heart
Heart is divided into four chambers:

7. The Heart Valves – Located between the atria and the ventricles
When blood flows from the atria to ventricles valves open
When ventricles contract, the valves close
Prevents blood from flowing back to the atria
also located at the
exits of each ventricle
System of valves keep
blood flowing in one
direction

8. The Hearts Blood Supply
The heart needs a constant blood supply of oxygen and nutrients
Coronary Arteries – branch from the aorta and
run through heart tissue
These arteries are relatively narrow despite the fact that the heart requires so much
Blocked arteries = muscle cells begin to die
Moments after oxygen is cut off
Leads to heart attack

9. The Hearts Blood Supply

10. Circulation

11. Circulation
Pulmonary Circulation – the right side of the heart pumps oxygen poor blood from the heart to the lungs

12. Circulation
Systemic Circulation – the left side of the heart pumps oxygen rich blood to the rest of the body

13. EKG (Electrocardiography)
Heartbeat
Two networks of muscle fibers coordinate the heart’s pumping action
When a single muscle fiber in either network is stimulated the entire network contracts.
EKG (Electrocardiography)
a test that records the electrical activity of the heart.

14. Heartbeat First: Atria Contract
Each contraction begins in a small group of cardiac muscle fibers called the SA Node
SA Node – sinoatrial node
Located in the Right Atrium
Sets the pace for the heart called the Pacemaker
SA Node fires
An electrical impulse spreads through the entire network of muscle fibers in the atria
Atria Contract

15. Second: Ventricles Contract
Heartbeat
Second: Ventricles Contract
The impulse from the SA Node is picked up by the AV (atrioventricular node) just like the SA Node
The impulse is delayed for a fraction of a second while the atria contract and pump blood into ventricles
Then the AV Node produces impulses that spred through the ventricles
Ventricles Contract – Pump blood Out

16. Heartbeat

17. Heartbeat Lub Dub Heart beat sound
Sound is the opening and closing of valves between atria and ventricle

18. Control of Heart Rate
Heart rate varies depending on your body’s need to take in oxygen and release carbon dioxide
Heat beat is not directly controlled by the nervous system
Autonomic nervous system does influence the activity of the SA node
Neurotransmitters released by the nervous system increase heart rate
Parasympathetic nervous system decrease heart rate

19. Blood Vessels Arteries
Carry blood from the heart to the tissues of the body
Carry oxygen rich blood (except for pulmonary artery)
Thick elastic walls
Withstand pressure produced by the heart
3 Layers:
Connective Tissue
Smooth Muscle
Endothelium

20. Blood Vessels Capillaries
Extremely, thin walls allow for gases (O2 & CO2), nutrients and waste products to diffuse in and out

21. Blood Vessels Veins Returns blood back to the heart
Blood flow is usually against gravity skeletal muscle aid in circulation
Vein also contain valves that prevent backflow

22. Blood Pressure
When the heart contracts it produces a wave of fluid pressure in the arteries known as blood pressure
Blood pressure is required to allow blood to move through the body
Sphygmomanometer – an inflatable cuff with a pump
and a meter used to measure
blood pressure

23. Blood Pressure Systolic Pressure – (High #) The force in the
arteries when the ventricle
contracts
Diastolic Pressure – (Low #) The last pulse heard, the
force in the arteries when the
ventricles relax.
A typical blood pressure is 120/80

24. Regulating Blood Pressure
Sensory receptors in blood vessels detect blood pressure and send impulses to the brain
High Blood Pressure – neurotransmitters that relax
the smooth muscles in the
blood vessel walls are
released
Low Blood Pressure – neurotransmitters are
released that cause the
smooth muscles in vessel
walls to contract.

25. Regulating Blood Pressure
Kidneys regulate Blood Pressure by affecting the volume of blood.
Triggered by hormones produced by the heart and other organs
High Blood Pressure causes kidneys to remove water and eliminate it as urine
Low Blood Pressure water is conserved

26. Blood Blood is a tissue Plasma 55% of total blood volume Straw colored
90% water & 10 % dissolved gases, salts, nutrients, proteins, cholesterol, and important compounds
Water helps control body temperature
Proteins – one type is Fibrinogen is necessary for blood to clot

27. Red Blood Cells (Erythrocytes)
Most numerous cells in blood
Main function is to transport oxygen
Hemoglobin – A protein binds with oxygen
Crimson color comes from the iron in hemoglobin
Also transports some carbon dioxide
Shape is important allows oxygen to bind easier

28. White Blood Cells (Leukocytes)
White Blood Cells guard against infection, fight parasites, and attack bacteria
White Blood Cells can increase in number dramatically during an infection

29. Blood
Platelets
Cell fragments
Aid in clotting

30. Circulatory System Disease
3 Common Diseases
Heart Disease
Atherosclerosis – a condition which fatty deposits
called plaque build up in artery walls
and eventually cause arteries to
stiffen
Angina – Chest pain, can be a sign of restricted blood
flow
Eventually heart can be weakened or damaged by oxygen deprivation, leading to heart failure

31. Circulatory System Disease
Heart Attack – occurs as heart muscle cells
become damaged and possibly
die
Can also damage SA and/or AV Nodes
Cocaine and cigarette smoking can lead to a heart attack
Symptoms:
Nausea
Shortness of breath
Chest pain
Pain in the neck, jaw, or left arm

32. Circulatory System Disease
Stroke
The sudden death of brain cells when their blood supply is interrupted
Some are caused bu blood clots in the brain
Also by the breaking of weak blood vessels
Symptoms:
Severe Headache
Numbness
Confusion
Trouble speaking

33. Circulatory System Disease
Stroke
Results of a stroke depend on where in the brain they occur
Some cause death
Some paralysis or loss of speech
High Blood Pressure
AKA Hypertension – 140/90 or higher
Heart damage can occur because the heart struggles to push blood through vessels

34. Circulatory System Disease
High Blood Pressure
Also tears small blood vessels
Stiffened arteries from atherosclerosis can contribute to high blood pressure
Uncontrolled High Blood Pressure can lead to :
Heart attack
Stroke
Kidney damage
Also known as the silent killer – you can have it for years till one of the above happens

35. Circulatory System Disease
Cholesterol
A lipid
Part of animal cell membrane
Also used in the synthesis of some hormones
Bile
Vitamin D

36. Circulatory System Disease
Cholesterol
It is transported around the body by two types of lipoproteins
Low – Density Lipoprotein (LDL)
High Density Lipoprotein (HDL)
LDL – Bad Protein carrier
HDL – generally transports excess
cholesterol from body to the liver
for removal

37. Circulatory System Disease
Cholesterol
Measuring cholesterol is actually measuring lipoproteins
Normal cholesterol levels range from 100 – 200 milligrams per deciliter
LDL should be below 100
HDL for males < 40 and for females < 50

38. Circulatory System Disease
Cholesterol
Source
The liver manufactures cholesterol
Consumed in:

39. Circulatory System Disease
Cholesterol
Research indicates that high cholesterol, along with other risk factors, lead to atherosclerosis and high risk of a heart attack

40. Circulatory System Disease
Cholesterol
LDL Receptors
In the Liver
Control the removal and determine the rate the liver will produce cholesterol

41. Circulatory System Disease
Cholesterol
Some people carry genes that produce defective LDL receptors
This creates two problems:
Liver can’t remove cholesterol from the blood
Liver does not get signal to stop making cholesterol

42. Circulatory System Disease
Cholesterol
A high cholesterol diet cause excess cholesterol to be stored in the liver
Liver then stops making LDL receptors
Defect mimics genetic disorder
Treatment:
Statins – Block the synthesis of cholesterol in liver
- cells
Cause liver to produce LDL receptors thus remove cholesterol

43. Factures Affecting Blood Flow
Pressure
Blood Volume
Resistance
Viscosity
Disease
Exercise