Lecture 16: Anatomy of the Thorax & Breathing (ventilation) Flashcards
What are our body cavities lined with?
Serous membranes
What are serous membranes?
Double layer of secretory tissue with fluid between layers
What layer of serous membrane lies on the organ?
Visceral layer
What layer of serous membrane lies on the body wall?
Parietal layer
What are 2 examples of serous membrane in the Thoracic cavity?
- Pericardium
- Pleura
What is an examples of serous membrane in the Abdominopelvic cavity?
Peritoneum
What are 2 devisions of the thoracic cavity?
- Mediastinum
- Pleural cavities
What is contained within the Mediastinum?
3
- Heart
- Vessels
- Pericardium
What is contained within 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 the neck
What is the Inferior boundary of the Thoracic cavity?
Diaphragm
Why are the Pleural cavities seperate?
So if one stops functioning, you have another
What is the hilum of the lung?
Where the primary bronchus and vessels enter
What is ventilation of the lung driven by?
Pressure changes in the thoracic cavity
What is the relationship of pressure to volume?
Inversely proportional
What happens when the volume of the thorax is changed?
The pressure is also changed
What changes occur to volume during inspiration?
Volume increases
What changes occur to volume during expiration?
Volume decreases
What law determines the relationship between pressure and volume of a gas?
Boyle’s Law
What is Boyle’s law equation?
P = 1/V
What is pressure measured by?
Collisions
What does a smaller space mean for collisions and pressure?
More collisions therefore more pressure
What does a bigger space mean for collisions and pressure?
Less collision therefore less pressure
What does air try and move towards?
Lower pressure space
What needs to be established in order to breath?
A pressure gradient
Between breathes what happens to the pressure inside of and outside of the cavity?
They are equal
What happens to air flow when there is an increased volume in the thoracic cavity?
Air flows in due to an decrease in pressure
What happens to air flow when there is a decreased volume in the thoracic cavity?
Air flows out due to an increase of pressure
What connects the bone of the ribs to the sternum?
Costal (hyaline) cartilage
What type of joints are the sternocostal joints
Synovial, the exception being the 1st which is cartilaginous
How many sternocostal joints are their on either side of the sternum?
7
What connects the bone of the ribs to the costal cartilage?
Costochondral joints
What kind of joints are costochondral joints?
Cartilaginous
What connects costal cartilage from different ribs together?
Interchondral joints
What kind of joints are the interchondral joints?
Synovial
What kind of joint are between the thoracic vertebrae and the ribs?
Synovial joints
What is the name of the joint between the rib and the transverse process of vertebrae?
Costotransverse
What is the name of the joint between the rib and the body of vertebrae?
Costovertebral
What do the respiratory muscles do?
Move the rib cage allowing us to breathe
What are the primary inspiration muscles?
2
- Diaphragm
- Intercostals
When are accessory muscles activated?
Only when needed
What is the diaphragm?
A sheet of skeletal muscle
What does the diaphragm seperate?
The thorax from the abdomen
What is the shape of the diaphragm when relaxed?
Dome-shaped
What is the shape of the diaphragm when contracted?
Flattened
What does contraction of the diaphragm do to the thoracic/abdominopelvic cavity?
Expands the thoracic cavity, compresses the abdominopelvic cavity
What do intercostal muscles attach to and how do attach?
They attach too neighbouring ribs and they do so diagonally
What do the external intercostals do?
Lift the ribcage and expand the cavity
What type of inspiration are external intercostals used for?
Quiet and forced
What do the internal intercostals do?
Depress ribcage and decrease cavity
What does the diaphragm do during normal quiet inspiration?
Contracts thus flattening
What do the external intercostals do during normal quiet inspiration?
Contract lifting ribs
Along side the actions of quiet inspiration what happens during forced inspiration?
Accessory muscles contract to further expand the thoracic cavity
What does the diaphragm do during normal quiet expiration?
Relaxes thus going dome shaped
What do the external intercostals do during normal quiet expiration?
relax no longer lifting ribs
Along side the actions of quiet expiration what happens during forced expiration?
Internal intercostals contract depressing the ribs and accessory muscles contract to further decrease cavity volume
Because lung tissues is elastic what is it always trying to do?
Recoil
What do the pleura do to the lungs?
Make the lungs stick to the thoracic wall
What does lung volume do during inspiration?
Increases
What does lung volume do during expiration?
Decrease
What does the visceral pleura lie against?
The lungs
What does the parietal pleura lie against?
Thoracic wall
What is between the parietal and visceral pleura?
Pleural fluid
What does pleural fluid enable for the lungs movement?
Frictionless movement against other structures
What does the fluid bond of pleural fluid cause the lungs to do?
Stick to the thoracic wall
As the lungs are stuck to the thoracic wall what does thoracic wall movement cause?
Lung movement