Chapter 18 - heart and cardiovascular function Flashcards
Functions of Cardiovascular system
- transport gas, nutrients, hormones, and metabolic waste
- regulation of pH and ion composition
- restriction of fluid loss
- Defense against toxins and pathogens
- Stabilization of body temp
Components of Cardiovascular system
- blood: transport medium
- heart: muscular pump that moves blood around the body
- system of tubes/ vessels: arteries, veins, capillaries
Pulmonary
lungs
Systemic
rest of body
Heart location
in mediastinum in thoracic cavity, within pericardial cavity surrounded by pericardial fluid
Pericardium is composed of 2 parts
a tough fibrous layer lined by delicate serous membrane
Fibrous pericardium
- very dense
- non-flexible tissue
- protects and anchor the heart
Serous membrane - 2 layers
- Visceral pericardium:
- Parietal pericardium
Cardiac tissue
- Pericardium
- Myocardium
- Endocardium
Pericardium
- connective tissue sac that surrounds the heart
- pericardial cavity contains serous fluid
Myocardium
hearts muscular layer
Endocardium
- layer squamous epithelial tissue
- intimately covers the inner chambers of heart
Cardiac muscle is
- striated
- branch
- only 1 nucleus
Right atrium receives blood from
vena cava
Left atrium receives blood from
pulmonary veins (lungs)
Right ventricle pumps blood into
lungs via pulmonary arteries
Left ventricle pumps blood into
body via aorta
Tricuspid
right AV valve
Biscuspid
left AV valve
Tricuspid and Biscuspid are _____ valves
Atrioventricular
Two semilunar valves
- btwn left ventricle and aorta
- btwn right ventricle and pulmonary artery
What determines the flow of blood in the heart and cause the valves to open and close?
pressure
How do the AV valves open
blood returning to heart forces it open
How to the AV valves close
-ventricles contract
Cardiac cycle refers to the
repetitive contraction and relaxation of heart
Systole
contraction
Diastole
relaxation
Cardiac cycle initiated by
SA node
Signal slightly delayed by
AV node
Extracellular Ca++ moves into the cells during depolarization, and creates a
plateau phase
Cardiac Cycle phases
- Ventricular filling
- Ventricular Systole
- Early Diastole
Ventricular filling
SA node depolarizes leading to atrial depolarization (p-wave)
Ventricular Systole
depolarization wave reaches ventricles and begin to contract (QRS waves)
-AV valve closes 1st sound
Early Diastole
aortic valve closes by pressure in aorta
-2nd sound
CO =
HR x SV
Cardiac reserve
difference btwn the CO at rest and the maximum CO
CHP in capillaries starts at ___ mm Hg arterial side, drops to ___ mm Hg on venous side
35/18
