The Cardio-Vascular (CV) System Flashcards
CV system Functions
Transport: essential food, oxygen, water, enzymes, hormones to cells of the body.
Remove: waste products to excretory organs
Components of CV system
- Heart
- Blood Vessels
- Blood
Location of the Heart
Situated in the thoracic cavity.
it lies behind the STERNUM in front of the SPINE, between the LUNGS & above the DIAPHRAGM
Structure of the Heart
Hollow
Cone Shaped
Muscular Organ
Walls of the Heart
3 main layers:
- pericardium (outer layer)
- Myocardium (middle layer)
- Endocardium (inner layer)
Name the Four Chambers of the heart
Left and right Atria.
Left and right ventricles
Describe the Atria
Two thinner walled upper chambers of the heart
Separated by the inter-atrial septum in an adult of normal health
Describe the Ventricles
Two thicker walled muscular lower chambers that receive blood form their respective atria.
They pump the blood either around the body (left) or through the lungs (right)
describe the Inter-ventricular Septum
A dividing wall of tissue which partitions the heart into left and right sides
describe the Atrio-ventricular septum
separates the atria from the ventricles
name the valves of the heart
Tricuspid valve
Pulmonary Semi-lunar valve
Bicuspid valve
Aortic Semi-lunar valve
Electrical Conduction System - name the components
specialised cardiac cells that produce electrical impulses to cause the heart to contract
- sino-atrial node
- atrio-ventricular node
- left & right bundle branches
- Conduction pathways (Purkinje fibres)
What Is the Cardiac Cycle
- 1 sec - Atrial Systole - contraction of atria
- 3 sec - Ventricular Systole - contraction of ventricles
- 4 sec - Cardiac Diastole - Relaxation phase
What is Cardiac Output (CO) and how is it calculated?
the amount of blood expelled form the ventricles in 1 minute.
SV x HR = CO
What is Stroke Volume (SV)
the amount of blood expelled from the ventricles in each contraction.
Nervous control
The heart is controlled primarily by the rate of self-excitation of its own tissue. HOWEVER, the Autonomic Nervous System does play a role.
Cardiovascular Centre
Located in the Medulla Oblongata. Sympathetic and Parasympathetic control regulates heart rate.
five types of Blood Vessels
Arteries Arterioles Capillaries Venules Veins
Blood Vessel composition
An outer fibrous sheath
A middle layer of muscle and elastic fibre
A smooth inner lining of Endothelium
Arteries
Carry blood away from the heart
Have a thick outer coat
Have a thick muscle layer
Arterioles
Smaller then arteries
Arterioles (and Venules) dilate or contact to control blood flow into and out of the capillary bed.
Capillaries
Have one cell thick walls
Allow the interchange of gasses
Transfer nutrients and waste products
Venules
Smaller then Veins.
Can dilate or contract to control blood flow into and out of the capillary bed.
Veins
Return blood to the heart
Have thinner walls then arteries
Some veins have valves to prevent the back flow of blood.
