Intro to CVS

●2025
P 1,2,3 : Not important
P 4 : Function of papillary ms "Q"
P 11 : nervous factors "Q" written & practical.

The Heart

💥 Discribtion :

-It is a muscular organ

- it is a bout 250 gm in adult females and 300 gm in adult males

- it's located near the Medline of the thoracic cavity in the Mediastinum

- it is surrounded by sac called pericardium That protect heart

💥 Layers of the heart Wall :

- epicardium

- myocardium

- endocardium

💥 Chambers of the heart:

It has four Chambers

- Right Atrium

- left Atrium

- Right ventricle

- Left ventricle

🛑 Important notes:

1- Right Atrium and left Atrium are separated by interatrial septum

2- Blood pass from right atrium to right ventricle through a valve called Tricuspid valve

3- Right ventricle and left ventricle are separated by interventricular septum

4- Blood passes from left Atrium to left ventricle through a valve called Mitral valve

💥 Heart valves:

- Atrioventricular valves

1- Tricuspid valve: between right atrium, ventricle

2- Mitral valve: between left atrium, ventricle

- semilunar valves

1- pulmonary valve: between right ventricle and pulmonary trunk

2- Aortic valve: between left ventricle and aorta

💥 Division of the circulation:

- sistmic circulation

Left side pump oxygenated blood to the body

- pulmonary circulation

Right side pump deoxygenated blood to the lungs

🛑 Important Question:

1- Enumerate Function of fibrous skeleton

- prevent overstretching of valves as blood passes through them

- it is a point of insertion for bundle of cardiac muscle fibers

- act as electrical insulator between atria , ventricles

2- Enumerate Function of valves:

- Allow blood flow in one direction when open and prevent back flow when close

3- When does an A V valve open?

when atrial pressure is higher than the ventricular pressure the valve open allowing blood move from atria to ventricles

4-give an small account on conducting system of the heart

- SAN: lies in the lateral and epicardial aspect of the junction between the SVC and RA

- AVN: lies at the bese of RA and its depolarization wave is conducted very slowly

- purkinje fibers: reaches the crest of the interventricular septum and devides into: right, left bundle branch.