A&P - Chapter 28 (Part 1) Flashcards
Where is the heart located?
In the mediastinum
- just off to the left
Where does the apex of the heart lie? (2)
- On the diaphragm
2. Just below the 2nd rib
What does the position of the heart allow?
CPR
- between the sternum and the thoracic vertebrae
What is the rough size of the heart?
Same size as your fist
What is the heart covered by?
Pericardium
Pericardium
Loose fitting sac
What are the 2 parts that make up the pericardium?
- Fibrous portion
2. Serous portion
Fibrous portion
Tough, loose fitting inextensible sac
What does the fibrous portion attach to?
The larger blood vessels that leave the top of the heart
What 2 layers does the serous portion have?
- Parietal layer
2. Visceral layer
Parietal layer
Lies the inside of the fibrous pericardium
- lines the wall
Visceral layer
Adheres to the outside of the heart
- lines the organ
What does the serous portion allow?
Lubrication so it decreases friction
Epicardium
Visceral layer of the serous portion of the pericardium
Myocardium
Cardiac muscle tissue that makes up the bulk of the heart wall/chamber
Synctium
Intercalated discs functional unit
- joined cells
Endocardium
Thin layer of very smooth tissue that lines the inside of each heart chamber as well as the blood vessels
How many chambers make up the heart?
4
- 2 atria
- 2 ventricles
What divides the 2 atria?
Interatrial septum
What kind of pressure is in the atrium?
Low pressure
Where does blood return to?
The atriums via the veins
What kind of walls make up the arterial chambers?
Smaller and thinner compared to the ventricles
What divides the 2 ventricles?
Interventricular septum
What are the ventricles known as?
The pumping chambers
Where does the blood leave the heart?
Via the ventricles
Why do the ventricles have thicker walls?
Because they pump blood to the rest of the body
Systole
Contraction of the heart
Diastole
Relaxation of the heart
What is the direction of the blood controlled by?
Valves
