Circulatory System: Cardiovascular Flashcards
What are the two branches if the circulatory system
- Cardiovascular
2. Lymphatic
Functions of the cardiovascular system
1. Transportation (Nutrients, wastes, hormones) 2. Immunity and Protection (Clotting, disease/infection) 3. Regulation (pH, body temperature, fluid levels)
Structures of the cardiovascular system
- Heart
- Blood Vessels
- Blood
Describe the structure of the heart
- Roughly sized of closed fist
- Sits almost in the middle of chest in the mediastinum
- 2/3rds of its mass is on the left
- Attached to diaphragm inferiorly
Functions of the heart
Pump, adaptation to changes, homeostasis
What are the inferior and superior portions of the heart called?
Inferior: Apex
Superior: Base
A mass of organs and tissues that separates the lungs boundaries
Mediastinum
Mediastinum boundaries
Superiorly: 1st Rib
Inferiorly: Diaphragm
Anteriorly: Sternum
Posteriorly: Vertebral Column
What does the mediastinum contain?
- Heart and its large vessels
- Trachea
- Esophagus
- Thymus and Lymph Nodes
- Connective Tissue
CT membrane that surrounds and protects the heart
Pericardium
Two parts of the pericardium
- Fibrous Pericardium
2. Serous Pericardium
Structure of the Fibrous Pericardium
- Most superficial
- Tough, inelastic, dense irregular CT
How does the Fibrous Pericardium attach?
- Diaphragm inferiorly
- To CT of the blood vessels superiorly
What does the fibrous pericardium do?
Holds heart in the mediastinum and allows for movement
Structure of the Serous Pericardium
- Thinner, deep to fibrous
- Forms a double layer around the heart
Inner/outer layer of serous pericardium
Inner: Visceral Layer
Outer: Parietal Layer
Where is the Parietal layer of the serous pericardium
Fused to fibrous pericardium
Where is the Visceral layer of serous pericardium
Attached to the heart muscle
Visceral Layer of Serous Pericardium A.k.a
Epicardium
The space between the parietal and visceral layers of the pericardium. Filled with what, for what?
Pericardial Cavity
Filled with pericardial fluid to reduce friction
3 Heart Wall Layers
- Epicardium
- Myocardium
- Endocardium
Epicardium A.k.a
Visceral layer of the serous pericardium
Describe epicardium
Simple squamous epithelium and CT
-Gives outer surface a smooth, slippery texture
Describe myocardium
Cardiac muscle tissue
-Site of contraction
Describe endocardium
Endothelium overlying a thin layer of CT
-Provides a smooth lining for the chambers and valves of the heart
The layer of simple squamous epithelium that lines the cavities of the heart, blood vessels, and lymphatic vessels
Endothelium
What are the 4 chambers of the heart?
2 Atria, 2 Ventricles
Superior heart chambers
Atria
Receive blood from veins returning to the heart
Atria
Inferior heart chambers
Ventricles
Receive and eject out into arteries
Ventricles
Where do ventricles get their blood?
Atria
A dividing wall
Septa, sing septum
Dividing wall of the 2 atria
Interatrial Septum
Dividing wall of the 2 ventricles
Interventricular Septum
Carry blood towards heart
Veins
Carry blood away from the heart
Arteries
The right atrium receives blood from three veins. Name them
- Superior Vena Cava
- Inferior Vena Cava
- Coronary Sinus
Blood passes from the right atrium through to the right ventricle. How?
Through the right atrioventricular (AV) valve
Right Atrioventricular valve A.k.a
Tricuspid Valve
The cusps of the Tricuspid valve are connected by ______ called _____.
Tendon-like cords called Chordae Tendineae
Chordae Tendineae are anchored to the ventricular wall by _______.
Papillary Muscles
Blood is ejected from the right ventricle into the pulmonary trunk through which valve?
Pulmonary Semilunar Valve
Pulmonary trunk divides into..
Left and right pulmonary arteries
Left atrium receives blood from ____.
4 Pulmonary veins
Blood passes from the left atrium to the left ventricle through which valve?
Left Atrioventricular valve (AV)
Left Atrioventricular Valve A.k.a
Bicuspid valve, mitral valve
Which is the thickest chamber of the heart
Left Ventricle
Cusps of the bicuspid valve are connected by..
Tendon-like cords called chordae tenineae (same as tricuspid valve)
Blood is ejected by the left ventricle through ____valve into the ____.
Aortic semilunar valve, Aorta
Where does the blood in the aorta flow?
- Around the body
- Some into coronary arteries, which supplies heart with oxygen-rich blood
What happens in a Atrioventricular Valve opening/closing?
- blood into atria, increases pressure
- pressure opens valves
- blood into ventricles, decrease pressure
- decrease pressure closes valves
- papillary muscles contract prevent valves forced open the wrong way
Pulmonary and Semilunar Semilunar Valves opening/closing
- ventricles contract, blood in, increase pressure
- pressure closes AV valves, opens pulmonary/aortic valves
- blood into arteries (pulmonary, aorta)
- ventricles relax, blood in arteries flows back to heart
- fills cusps of semilunar valves, they close
What are the “lub-dup” sounds of the heart?
“Lub”: blood turbulence associated with closing of AV valves
“Dub”: blood turbulence with closing semilunar valves
Pulmonary and Systemic Circulation happen on which sides of the heart?
Pulmonary: Right Side
Systemic: Left Side
What happens in pulmonary circulation?
- Deoxygenated blood returns from body tissue, enters right atrium
- Pumped into right ventricle, blood into pulmonary arteries
- Arteries take blood to lungs to clear CO2 and pick up O2
- Oxygenated blood returns to heart (pulmonary veins) and enters left atrium
What happens in systemic circulation?
- Oxygenated blood returns from lungs, enters left atrium
- Blood pumped into left ventricle
- Eject blood into aorta and out into body tissue
- Tissues use O2 and release CO2, makes its way to right atrium (now deoxygenated)
What is coronary circulation? How does it happen?
Heart’s supply of blood circulation
- Coronary arteries branch off from the aorta and encircle heart
- Heart gets blood between beats.
Specialized cardiac muscles that generate their own APs
Autorhythmic fibres
-Self excitable!
What do Autorhythmic Fibres do?
- Set rhythm of APs that cause contraction
2. Form a conduction system
What is the Conduction System?
Pathway along which APs progress through the heart
APs propagate through the conduction system in a specific sequence:
- SA node
- Atria
- AV node
- Bundle of His
- Bundle Branches
- Purkinje Fibres
- Ventricles
Where is the SA (sinoatrial node) found?
Right atrial wall