Lecture 16: ANATOMY OF THE THORAX AND BREATHING Flashcards
What are our body cavities lined with?
Serous membranes
Where is the visceral layer of a serous membrane found?
On the organ
Where is the parietal layer of the serous membrane found?
On the body wall
What are the serous membranes in the thoracic cavity?
Pericardium (surrounds heart) and pleura (surrounds lungs)
What is the serous membrane in the abdominopelvic cavity?
Peritoneum
What does the thoracic cavity contain?
Mediastinum in the middle and pleural cavities either side
What is in the mediastinum?
Heart, vessels and pericardium
What is in the pleural cavities?
Lungs
What is the anterior boundary of the thoracic cavity?
Sternum
What is the posterior boundary of the thoracic cavity?
Thoracic vertebrae
What is the lateral boundary of the thoracic cavity?
Ribs
What is the superior boundary of the thoracic cavity?
Base of neck
What is the inferior boundary of the thoracic cavity?
Diaphragm
What is the relationship between pressure and volume?
Pressure is inversely proportional to volume
What happens if we change the volume of the thorax?
We change the pressure
What happens to volume and pressure during inspiration?
volume increases and pressure decreases
What happens to volume and pressure during expiration?
volume decreases and pressure increases
What is Boyles law?
P=1/V
What is pressure measured by?
Collisions
What does a smaller space mean?
More collisions and increased pressure
What does a bigger space mean?
Less collisions and decreased pressure
Where will air move?
To a lower pressure space
What needs to be established to breathe?
A pressure gradient so air can move
What is the pressure between breaths?
Pressure inside cavity is equal to pressure outside cavity so there is no gradient
What is the pressure during inspiration/inhalation?
Increased volume of thorax, therefore decrease pressure so pressure outside is greater than pressure inside and air flows in
What is the pressure during expiration/exhalation?
Decreased volume of thorax, therefore increased pressure so pressure outside is less than pressure inside and air flows out
How does the sternum connect to ribs?
Via costal cartilage (hyaline)
How many synovial joints on each side of the sternum?
6