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What is the thoracic cavity bounded by?
- Anteriorly: Sternum & costal cartilages
- Posteriorly: Thoracic Vertebrae
- Laterally: Ribs
- Inferiorly: Diaphragm
Name the parts of the sternum superior to Inferior:
- Xiphoid process
Describe the twelve ribs:
- Posteriorly attached to the thoracic vertebrae.
- Seven true ribs: Connected to the sternum by costal cartilage.
- Three false ribs: Attached to the sternum indirectly by costal cartilage.
- Two false (floating) ribs: No attachment to the sternum.
Name the 3 divisions of the thoracic cavity:
- Right pleural cavity; Right lung: 3 lobes
- Left pleural cavity; Left lung: 2 lobes
- Lymph nodes
- Heart with great vessels
Where can pleura be found?
- Parietal pleura: Lining the inner surface of ribs, Pericardium of the heart and superior surface of the diaphragm.
- Visceral pleura: Covers the outside of each lung.
- Pleural space: The space between the parietal pleural & visceral pleural; contains serous fluid that prevents friction between the lungs & pleura during respiration.
What principal muscles are associated with inspiration?
Diaphragm, external intercostals.
What accessory muscles are associated with respiration?
Sternocleid mastoid & scalenes.
What principal muscles are associated with expiration?
Internal intercostals, external oblique, internal oblique, transversus abdominis, & rectus abdominis.
What are the acts of respiration?
- (1) Diaphragm & external intercostals muscles contract.
- (2) Ribs & sternum elevate.
- (3) Size of thoracic cavity increases.
- (4) Pulmonary pressure decreases forcing air into the lungs.
Extends from larynx to bronchi. Formed by smooth muscle, hyaline cartilage (C-shaped rings, prevents trachea from collapsing). Inner wall lined with ciliated mucosa. Functions as a air way passage for the lungs.
Divide into the left & right Bronchi at the carina. Composed of smooth muscle & cartilaginous rings. Inner wall composed with ciliated mucosa (composed of goblet cells). Goblet cells trap foreign particles, cilia pass particles into throat (to be expelled, prevents respiratory tract infection).
Explain the bronchial division;
- (1) Bronchus enters lung, divides into secondary lobar branches.
- (2) lobar branches divides into segmental bronchi, then dividing into bronchioles ending in alveolar duct & alveoli.
Composed of simple squamous epithelium. Exchanges O & CO2.
Where can the lungs be found?
Between the clavicle to the diaphragm.
What structures can be found in the lungs?
Bronchus, pulmonary artery, superior pulmonary vein, inferior pulmonary vein, lymphatic vessels.
Where is the hilum on the lungs located?
On the medial side of each lung.
When does the bronchus and other structures enter the lung?
In the hilum.
Name the lobes of the left lung, and what are they separated by?
Superior & inferior lobe. Separated by fissure.
Name the lobes of the right lung, and what are they separated by?
Superior, middle, inferior, separated by the fissure.
Blood low in oxygen travels from?
Right ventricle--> left branch ofthe pulmonary artery -->left lung to be oxygenated.
Path way of oxygenated blood?
Leaves lungs through the pulmonary veins, then enters left atrium of heart.
What is the location of the heart?
Located within mediastinum, rest behind the sternum & on the diaphragm.
What is the pericardium for?
Protects the heart.
What is the Fibrous pericardium?
Outer layer of pericardium, fits loosely around heart & attaches to large blood vessels.
Name the substructures of the serous pericardium;
- Parietal layer: Lines the inside of the fibrous pericardium.
- Visceral layer: Attaches to the surface of the heart.
- Pericardial space: Space between the two layers, contains pericardial fluid, acts as lubricant allowing heart to easily contract.
Name the layers of the heart, starting from the outer layer to the inner layer;
- Epicardium: Outer layer of heart.
- Myocardium: Muscle layer, helps contract and force blood from the hearts chambers.
- Endocardium: Inner lining of the heart wall, lines all of the heart's chambers & valves, composed of endothelial tissue.
Name the four chamber of the heart:
- Two atria (upper chambers)
- Two ventricles (lower chambers)
Describe the atria:
Receives blood, has thinner walls, divided by the interatrial septum.
Describe the ventricles:
Pumps blood into arteries (leads away from heart), thicker myocardium, right ventricle pumps blood into lungs, left ventricle pumps blood into arteries that transports blood to all other regions of the body, divided by the interventricular septum.
Where is the atriventricular valve located?
Between each atrium & ventricle.
Where is the tricuspid valve located?
Between the right atrium & the right ventricle.
What happens when the B.P increases in the right atrium?
The tricuspid valves open, allowing blood to flow to the right ventricle.
What happens when the pressure in the right ventricle is greater than the pressure in the right atrium?
The bicuspid closes.
Describe the blood flow through the heart;
Deoxygenated blood enters --> Superior Vena Cava --> Right Atrium --> Tricuspid Valve --> Right Ventricle --> Semilunar Valve --> Pulmonary Artery --> Lungs --> blood is now oxygenated --> Left Atrium --> Mitral Valve --> Left Ventricle --> Aortic Semilunar Valve --> Aorta --> Rest of body
What two coronary arteries originate from the right coronary aorta?
The left & right coronary artery.
What artery branches to both ventricles?
Posterior descending artery.
What artery branches into the right ventricle and right atrium?
What artery supplies blood to both ventricles?
Anterior descending artery.
What artery supplies blood to the left ventricle & left atrium?
What is a cardiac cycle?
All actions that happen during a single heartbeat.
What is a systole?
The phase of contraction.
What is a diastole?
The phase of relaxation.
What is a atrial contract?
The forcing of blood into the ventricles.
The cardiac conduction system coordinates what?
The events of the cardiac cycle.
Where is the SA node located? What is it known as? And what is its function?
In the right atrial wall under the opening of the superior vena cava. The "pacemaker of the heart". To fire an electrical impulse that travels through the myocardium and stimulates the contraction in a rhythmic manner.
Where is the AV node located? Impulses from where travels down here? What does it provide? And why do action potential slows down here?
Located in the interatrial septum. Impulses from the SA node. It provides conduction pathway between atrium & ventricles. Because fibers are smaller.
What does the bundle of his connect?
The atria & ventricle.
What electrical impulses enters the purkinje fibers? And they spread impulses to what?
Bundle of His. The apex.
What are parasympathetic nerve fibers responsible for?
Slowing down the heart rate.
What does the sympathetic division secrete ( accelerates heart rate)?
What is the normal resting heart rate for an adult?
When does the heart begin to develop?
Before the end of the 3rd week.
What are the 5 specific regions of the primitive heart tube?
Ventricle, Sinus venosus, Atrium, Bulbus cordis, Truncus arteriosus.
What does the ventricle turn into?
What does the sinus venosus & atrium turn into?
Inferior & superior vena cava, & atrial chambers.
What does the bulbus cordis & truncus arteriosus turn into?
The pulmonary trunk & aortic trunk.
When does the myocardial contraction begin by?
The beginning of the 4th week.
By what week does the interventricular & interatrial septum develop?
By the 7th week
The opening between the two atrial chambers is called the _____?
When does foramen ovale close? The depression left in the interatrial septum is called the what?
At birth. Fossa ovalis
What is the placentas function?
To interchange gases, nutrients, and waste between the fetal and maternal blood.
What do the umbilical arteries do?
Carry fetal blood to the placenta.
What does the umbilical vein do?
Returns blood from the placenta to the fetus.
What makes up the umbilical cord?
The two umbilical arteries and the one umbilical vein.
What structure is the continuation of the umbilical vein?
The ductus venosus.
Most of the blood from the placenta is move through the what and into the what?
Ductus venosus and into the inferior vena cava.
The ductus arteriosus connects the what to the what, allowing what to happen?
The ductus arteriosus connects the pulmonary artery to the descending aorta, allowing blood to enter into the fetal circulation without going into the lungs.
In a fetus what is the foramen ovale for?
Is a passage way for blood from the right atrium into the left atrium.
What happens to the umbilical arteries and umbilical vein after birth?
It looses it its function.
What happens to the ductus venosus?
It becomes the ligament venous of the liver.
What happens to the umbilical vein?
It turns into the round ligament of the liver.
What happens to the ductus arteriosus?
It becomes into the fibrous cord that helps stabilize the aorta and pulmonary artery within the thoracic cavity.
After birth what happens to the right ventricle?
It ejects all of it's blood into the pulmonary circulation, and the normal cardiopulmonary circuit is established.