Circulatory Systemcirculatory system

circulatory sustem2

Vocabulary

• Brady- slow• Tachy- fast• Diastol- dilation

• -gram- written• -syn-together• Systol- contraction

Functions

• To take oxygen and nutrients to all parts of the body• To take carbon dioxide and waste products out of

the body

2 Pathways

• Pulmonary- sends oxygen-depleted blood to the lungs to pick up oxygen• Systemic- sends oxygenated blood and nutrients to

the body and removes waste

Heart

• Pericardium- the membrane that encloses the heart• Parietal Pericardium- inner lining of the

pericardium• Visceral Pericardium- innermost layer surrounding

the heart

Layers of the heart muscle

• Epicardium- outer layer• Protects the heart by reducing friction

• Myocardium- cardiac muscle- Pumps blood out of the heart• Endocardium- inner layer of the heart- Contains

blood vessels and purkinje fibers

Chambers of the heart

• Atria- upper chambers; receive blood returning to the heart• Ventricles- lower chambers; receive blood from the

atria and force blood out into the arteries

Chambers of the heart

• Septum- a solid wall-like structure separating the atria and ventricles so that blood from one side never mixes with the other side• Atrioventrical valve (AV valve)- ensures one way

blood flow between atria and ventricles

Blood supply to the heart

• Coronary Arteries- supply blood to the heart• Cardiac Veins- drain blood from the heart

Pathways • Veins and venuoles- bring deoxygenated blood

from the body to the heart• Arteries and capillaries- bring oxygen-rich blood to

body parts

Heart Sounds• Valves closing (lubb-dupp)• Lubb: ventricular contraction• Dubb: ventricular relaxation

Sanode

• Sinoatrial Node- pacemaker of the heart• Nerve cells touch so impulse spreads easily across

the heart• Average 78 BPM in adults

Purkinje Fibers

• Purkinje fibers- cardiac muscle fibers that conduct nerve impulses• Electrocardiogram (ECG)- a record of the electrical

changes in the heart

Heart beat

• Tachycardia- irregularly fast heart beat 100+ beats per minute• Bradycardia- reduced heart rate fewer than 60

BPM

Blood vessels

• Vasoconstriction- (contract) reduced diameter of blood vessels• Vasodilation- (relaxed) increased diameter of blood

vessels

Blood Pressure

• Systolic Pressure- maximum contraction of ventricles• Diastolic Pressure- when the ventricles are at their

lowest and are about to contract again• Sphygmomanometer- instrument used to measure

blood pressure

Influence of BP

• Blood volume- 5 liters is normal• Peripheral resistance- friction between blood and

blood vessels• Blood viscosity- how resistant blood is to flowing• High viscosity = slow flow• Low viscosity = fast flow* Blood cell count and plasma change blood viscosity

Blood Pressure

• Hypertension = high blood pressure• Consequences- myocardium thickens, enlargement of

heart• Causes- obesity, diet (salt), heart disease, kidney

disease, psychological stress