Circulatory System Flashcards
What is the middle mediastinum?
The space between the lungs along the midline
Where is the middle mediastinum?
Between sternal angle/T4 (anteriorly) and diaphragm (posteriorly)
What are the 3 components of the middle mediastinum?
- Pericardial sac (main)
- Heart
- Roots of great vessels (5: Aorta, Pulmonary trunk, Pulmonary veins, Inferior vena cava, Superior vena cava)
What innervates the diaphragm?
PHRENIC NERVE
Where does the phrenic nerve come from and attach to?
comes from cranial roots C3-C5
attaches to pericardial sac
What is the blood supply of the middle mediastinum?
internal thoracic artery/vein
Where is the location of the heart?
SUPERIOR: sternal angle (2nd costal cartilage)
INFERIOR: 5th intercostal space
What is the size of a person’s heart?
The size of the individual’s fist
What are the layers of the pericardium?
- Fibrous layer (OUTER)
- Serous layer (FOLDS IN ON ITSELF FOR 2 LAYERS)
a. Parietal
b. Visceral
What is between the parietal and visceral layers of the serous layers of the pericardium and what is its function?
PERICARDIAL SPACE
shock absorption and cushion
What is the order of the pericardium layers from outside to inside?
- Fibrous layer
- Parietal serous layer (serous)
- Pericardial space
- Visceral serous layer (epicardium)
What are the three layers of the heart?
- Endocardium
- Myocardium
- Epicardium
What are the characteristics of cardiac muscle?
- striated
- branched
- intercalated discs
- many mitochondria
- self-contractile
How many chambers of the heart are there?
FOUR
2 atria (receiving)
2 ventricles (pumping)
What is the flow of blood to and from the heart?
- Inferior/Superior vena cava
- Right atrium
- Right ventricle
- Pulmonary trunk
- Lungs
- Pulmonary vein
- Left atrium
- Left ventricle
- Aorta
What is the fossa ovalis?
depression in right atrium in adults but foramen in babies
What is the right atrium (external) characteristics?
- 1/4 of the anterior surface
- receiving chamber for systemic circulation
- have a right auricle (flap/ear)
What is the coronary sinus?
Large vein in the heart that drains deoxygenated blood from the heart muscle into the right atrium
What is the crista terminalis?
Separates the smooth wall veinous portion and pectinate muscle
What is the pectinate muscles?
The contractile portion of the atrium
Which valve connects the right atrium and the right ventricle?
right atrioventricular (AV) valve
(tricuspid valvue)
How many flaps does the right AV valve have?
THREE
What is papillary muscle in the right ventricle?
projections out of the walls of the ventricle
small pillar-like projections
The ____________________________ valve projects into the right ventricle.
right atrioventricular (AV)
What is the chordae tendinae?
Tendinous chords that attach to the flaps of the valve to the papillary muscle to prevent the blowback of blood
What is trabeculae carnae?
striations int he wall
pull walls of ventricle closed during contractions
Which valve in the heart does not have chordae tendinae?
PULMONARY VALVE
What valve is located between the right ventricle and the pulmonary trunk?
PULMONARY VALVE
Which valve is located between the left atrium and ventricle?
left atrioventricular (AV) valve
What is different about the pulmonary vein?
IT IS ONE OF THE ONLY VEINS THAT CARRIES OXYGENATED BLOOD
(from lungs back to heart)
What valve is between the left ventricle and the aorta?
Aortic valve
How many cusps does the aortic valve have?
THREE
What is the left flow of blood through the heart called?
SYSTEMIC CIRCUIT
OXYGENATED
What is the right flow of blood through the heart called?
PULMONARY CIRCUIT
DEOXYGENATED
What are some changes at birth?
- Foramen ovale –> fossa ovale
- Ductus arteriosus –> ligamentum arteriosum
- Ductus venosus –> ligamentum venosum
- Umbilical vein –> closed
What is special about fetal circulation?
has shunt to bypass liver (due to placenta)
1. Umbilical vein
2. Ductus venosus
3. Foramen ovale
4. Ductus arteriosus
5. Umbilical arteries
What is the tricuspid valve primarily made out of?
Fibrous tissue
The aortic valve has small holes/openings behind the right and left flaps. What are these for?
for coronary arteries
COVERED BY THE FLAPS when blood flows through
What are the two coronary arteries?
- Right coronary artery
- Left coronary artery
What are the coronary veins?
- great cardiac vein –> coronary sinus, middle cardiac vein, small cardiac vein
- coronary sinus –> right atrium
What are the two types of controls for the heartbeat?
- Intrinsic control
- Extrinsic control
What is intrinsic control of the heartbeat?
From special tissues in the heart
2 “nodes”
1. Sinoatrial node (SA) - PACEMAKER
2. Atrioventricular node (AV) - down septum
Purkinje fibers
Bundle of His
What is the extrinsic control of the heartbeat?
Parasympathetic system
Autonomic fibers synapse on SA node
What are the parasympathetics of the extrinsic control of the heartbeat?
slow heartbeat
from VAGUS nerve (CN X)
What are the sympathetics of the extrinsic control of the heartbeat?
speed up heartbeat
from CERVICAL to T1 SYMPATHETIC GANGLIA
Where is the cardiac plexus located?
below the aortic arch
anterior to the trachea split (carina)
Where does the preganglionic parasympathetics from the vagus nerve synapse?
in the cardiac plexus
Where do the postganglionic sympathetics come from?
Sympathetic chain ganglia
