06/08/2023 Notes Flashcards
What division of the nervous system innervates the heart?
Autonomic nervous system
What is the coronary plexus?
Both the sympathetic and parasympathetic innervation of the heart
What carries out sympathetic innervation of the heart, and what does it do?
nerve fibers form T1-T5 increase the heart rate and force of contractions
What causes parasympathetic innervation of the heart?
The medulla through CN X decreases the heart rate but does not affect force of contractions
What do autonomic centers in the brainstem do for the heart?
Increase/decrease the heartbeat, but does NOT initiate the heartbeat
What is a cardiac cycle?
Inclusive period from the start of one heartbeat to the initiation of the next
What is systole?
Contraction of the heart that force blood into another chamber of blood vessel
What is diastole?
Relaxation of the heart that allows the chambers to fully fill with blood
At the beginning of the cardiac cycle, which chambers contract simultaneously?
Left and right atria
During atrial systole, what happens?
Blood returning from the superior/inferior vena cava and the coronary sinus (right atrium) and pulmonary veins (left atrium) is forced through the open AV valves into ventricles
Once atrial diastole occurs, what happens?
Both the left and right ventricles contract simultaneously
What happens to AV valves as the ventricle contract?
AV valves shut tight and blood pushes against the cusp to form a seal
What prevents the heart valves from everting?
Papillary muscles and chordae tenineae
When semilunar valves are forced open, where does blood travel?
Into the pulmonary trunk and aorta
During ventricle diastole, how does blood travel?
Blood flows passively from the atria to ventricles through open AV valves
During the last half of the cardiac cycle, what state are all four heart chambers in?
Diastole
Give a summary of blood flow during 1 cardiac cycle.
Pressure on the blood in heart chambers increase/decrease during contraction/relaxation;
Blood flows from veins continuously into both atria with low pressure;
Blood flows from atria to ventricles if AV valves are open;
Systole increases pressure on blood in ventricles and forced to enter arterial trunks
When does most ventricular filling of blood occur?
70% occurs when chambers are in diastole and atrial pressure is greater than ventricular pressure
What is brachycardia?
Abnormally slow heartbeat less than 50 bpm
What is athlete’s brachycardia?
A beneficial adaptation resulting from a muscular heart, healthy circulatory system, and excellent lung capacity
What is the foramen ovale?
A one-way flutter valve in the embryo that shunts blood from the right atrium to the left atrium through the septum primum to the rest of the body since the lungs are not functional
When a baby is born with functional lungs, what happens to the foramen ovale?
The septum primum is forced shut from blood at the left atrium to turn it into a closed interatrial septum; eventually the fossa ovalis forms
What are 2 other names for patent foramen ovale?
Perforated fossa ovalis or atrial septal defect
What is a patent foramen ovale?
When the septum primum does not fully fuse and blood flows directly from the right atrium to the left atrium and vice versa, which may lead to poor pulmonary circulation and undesired material to travel directly from venous circulation to arterial circulation
How much of the adult population suffers from perforated fossa ovalis?
30%
What are blood vessels analogous to?
Highway since they are an efficient mode of transportation for oxygen, carbon dioxide, nutrients, hormones, and waste products
Are blood vessels rigid and immobile?
No, they can pulsate and change shape in accordance to the body’s needs
What composes the systemic circulation?
Consists of left atrium, left ventricle, and all other named vessels that travel the body until it reaches the right atrium
What composes the pulmonary circualtion?
Right atrium, right ventricle, and all other named vessels until it reaches the left atrium
What are the 3 types of blood vessels?
Arteries, veins, and capillaries
What are arteries?
Blood vessels that carry blood FROM the heart and branch into smaller arteries and arterioles as they get further from the heart
What are veins?
Receives blood from venules and carry blood TO the heart and become larger as they get closer to the heart
What occurs in capillaries?
Exchange of nutrients and oxygen between tissue and muscles
What is an anastomosis?
A site where two or more arteries or veins merge together to supply the same body region
What do arterial anastomosis do?
Supply alternate blood routes to body tissues or organs