Human Anatomy CH 19 Flashcards
What is the heart?
Muscular double pump
What are the two functions of the heart? Be sure to describe their functions
- Pulmonary Circuit - Right side receives oxygen-poor blood from the body and pumps it to the lungs
- Systemic Circuit - Left side receives oxygenated blood from lungs and pumps throughout body
What are the atria’s functions?
Receives blood from the pulmonary and systemic circuit
What is the ventricles?
Pumping chambers of the heart
What is the weight of a healthy heart?
250-350 grams
Where is the heart located?
Between the lungs
The heart is the largest organ of the ________
Mediastinum
What lies to the left of the midline of the heart?
Apex
What is the broad posterior surface of the heart?
Base
Describe where the superior right area of the heart
At costal cartilage of third rib and sternum
Describe where the inferior right area of the heart
At costal cartilage of sixth rib lateral to sternum
Describe where the superior left area of the heart
At costal cartilage of second rib lateral to the sternum
Describe where the inferior left area of the heart
Lies in the 5th intercostal space at the midclavicular line
What are the two primary layers that the pericardium is divided into?
- Fibrous pericardium
- Serous pericardium
What type of tissue is the fibrous pericardium made out of?
Strong layer of dense connective tissue
What two layers form the SEROUS pericardium?
- Parietal layer of serous pericardium
- Visceral layer of serous pericardium
What are the 3 layers of the heart wall and their qualities?
- Epicardium - Visceral layer of the serous pericardium
- Myocardium - Consists of cardiac muscle that is arranged in circular and spiral patterns
- Endocardium - Endothelium resting on a layer of connective tissue
What are 3 external markings of the heart chambers?
- Coronary sulcus
- Anterior interventricular sulcus
- Posterior interventricular sulcus
What forms the right border of the heart?
Right atrium
Where does the right atrium receive oxygen-poor blood from (which vessels)? What circuit does it come from?
Systemic circuit
1. Superior vena cava
2. Inferior vena cava
3. Coronary sinus
What are the ridges inside the anterior of right atrium called?
Pectinate muscles
What landmark is used to locate veins entering the right atrium?
Crista Terminalis
The fossa ovalis is a remnant of the _________
Foramen Ovale
Where does the right ventricle receive blood from?
Right atrium through the right atrioventricular valve (tricuspid valve)
Where does the right ventricle pump blood into?
Pulmonary circuit through the pulmonary trunk
What are the 3 parts of the internal walls of the right and left ventricle?
- Trabculae carnae
- Papillary muscles
- Chordae tendinae
Where is the pulmonary semilunar valve located?
Opening of right ventricle and pulmonary trunk
What makes up the heart’s posterior surface?
Left atrium
Where does the left atrium receive oxygen-rich blood from?
Pulmonary veins
The left atrium opens into the left ventricle through __________ (list all 3 names)
- Left atrioventricular valve
- Bicuspid valve
- Mitral valve
What forms the apex of the heart?
Left ventricle
The right ventricle pumps blood through what circuit via what valve?
Systemic circuit via aortic semilunar valve
What is every valve composed of (include tissue type)?
Endocardium with connective tissue core
Where are the Atrioventricular (AV) valves located? What are their alternate names?
- Right AV valve = Tricuspid valve
- Left AV valve = Bicuspid valve
Where are the aortic and pulmonary valves located?
At junction of ventricles and great arteries
What surrounds all 4 valves? What kind of tissue is it composed of?
Cardiac skeleton; composed of dense connective tissue
What are the functions of the cardiac skeleton?
- Anchors valve cusps
- Prevents overdilation of valve openings
- Main points of insertion for cardiac muscle
- Blocks direct spread of electrical impulses
“Lub” is the sound of _______
AV valves closing
“Dub” is the sound of _______
Semilunar valves closing
Name the valve and what heart corner is best for hearing their valve sounds
- Pulmonary valve - Superior left corner
- Aortic valve - Superior right corner
- Mitral (Bicuspid) valve - At the apex
- Tricuspid valve - Inferior right corner
Describe ALL 10 steps of the pathway of blood through the heart (in order)
- Oxygen-rich blood is delivered to the body tissues (systemic circuit). Oxygen-poor blood returns from the body tissues back to the heart
- Coronary sinus, superior, and inferior vena cavae
- Right atrium
- Right ventricle
- Pulmonary trunk
- Oxygen-poor blood is carried in two pulmonary arteries to lungs (pulmonary circuit) to be oxygenated, then returns to the heart via four pulmonary veins
- Four pulmonary veins
- Left atrium
- Left ventricle
- Aorta
As a drop of blood passes through all structures sequentially, what happens to the atria and ventricles?
Atria contract together and ventricles contract together
How many beats per minute when the heart is resting?
70-80 beats per minute
What is the contraction of a heart chamber called?
Systole
What is the expansion of a heart chamber called?
Diastole
What does systole and diastole ALSO refer to?
Stage of heartbeat when ventricles contract and expand
Describe the walls of the atria and the ventricles
Atria - Thin walls
Ventricles - Thick walls
Describe the systemic circuit
It’s longer than the pulmonary circuit and offers greater resistance to blood flow
The left ventricle is _____________ than right ventricle because it _________________
three times thicker than right ventricle because it exerts more pumping force
The left ventricle flattens the right ventricle into what shape?
Crescent shape
What does cardiac muscle tissue form? What differentiates this type of tissue?
Myocardium; striated, like skeletal muscle
How do contractions affect the cardiac muscle tissue? How does cardiac muscle tissue help blood flow?
Contracts via sliding filament mechanism. Contractions pump blood through the heart and into blood vessels
Describe cardiac muscle cells
Short, branching, have one or two nuclei, and do not have fused colonies
What are intercalated discs?
Complex junctions that form cellular networks
What are cardiac muscle cells separated by?
Endomysium
What do cardiac muscle cells join together to form? What do they contain?
Binded together to form cardiac fibers that contain blood vessels and nerves
How are cellular networks of intercalated discs formed?
Adjacent sarcolemmas interlock
What are the 3 types of cell junctions
- Desmosomes
- Fasciae adherens - long desmosome-like junctions
- Gap junctions
How are cardiac muscle cells triggered to contract? Name all “3” steps. What does it trigger?
Triggers sliding filament mechanism
1. Ca2+ enters the sarcoplasm
1a. Signals sarcoplasmic reticulum to release Ca2+ ions
1b. Ions diffuse into sarcomeres
All cardiac cells are innervated. True or False?
False
What is rhythmicity (rhythmic heartbeat basis)?
Contractions in a rhythmic manner without innervation
What abilities do cardiac muscle tissue have?
- Generate and conduct impulses
- Signals cells to contract rhythmically
What is the ‘conducting system’?
Series of specialized cardiac muscle cells
What sets the inherent rate(heart rate) for contraction?
Sinoatrial (SA) Node
List the 5 steps of the conducting system. Remember to include WHERE they occur
- SA Node - Impulse generated - Right atrium
- AV Node - Impulse pauses - Bottom of right atrium
- AV Bundle connects atria and ventricles - Between atria and ventricles
- Bundle branches conducts impulses - Interventricular septum
- Subendocardial conducting network (Purkinje fibers) - Inner walls of the ventricles
What can alter the heart rate?
Visceral sensory fibers
Parasympathetic fibers
Where do the visceral sensory and parasympathetic fibers pass through?
Cardiac Plexus
Where do parasympathetic fibers branch from? What is their function?
Branches from: Vagus nerve
Function: Decreased heart rate
Where are the parasympathetic and sympathetic nerves restricted to?
SA Node, AV Node, and Coronary Arteries
What does the sympathetic nerve innervate that the parasympathetic DOES NOT?
Cardiac musculature throughout the heart
Where does the sympathetic nerves travel to? What is their function?
Travel to heart from cervical and upper thoracic chain ganglia
Function: Increases heart rate and strength of contraction
What is the autonomic input controlled by?
Cardiac centers in reticular formation of medulla
What are the two autonomic input centers? What do they influence?
- Cardioinhibitory center - Influences parasympathetic neurons
- Cardioacceleratory center - Influences sympathetic neurons
What do the coronary arteries supply blood to? List the 2 coronary arteries
Muscular walls and tissues of the heart
1. Right coronary artery
2. Left coronary artery
Where do the coronary arteries arise from?
Base of the aorta and run in the coronary sulcus
What does the left coronary artery (LCA) branch into?
Anterior interventricular artery and circumflex artery
What is the clinical name for the anterior interventricular artery?
Left anterior descending artery (LAD)
What descends in coronary sulcus?
Right coronary artery (RCA)
The right coronary artery branches to form __________ and ____________
Marginal artery & Posterior interventricular artery
What is the clinical name for the posterior interventricular artery?
Posterior descending artery (PDA)
What do the cardiac veins do?
Carry deoxygenated blood from the heart wall to the right atrium
Where do the cardiac veins occupy?
Sulci on the heart surface
What runs in the posterior part of the coronary sulcus? What is its function?
Coronary Sinus
Function: Returns majority of venous blood from the heart to the right atrium
What are the 3 tributaries of the coronary sinus?
- Great cardiac vein
- Middle cardiac vein
- Small cardiac vein
Name 4 coronary artery diseases and their defining feature
- Atherosclerosis - Fatty deposits
- Angina pectoris - Chest pain
- Myocardial infarction (heart attack) - Blocked coronary artery
- No pain or warning
What causes heart failure?
The heart progressively weakens, which results in the body’s demands for oxygenated blood not being met
What disorder happens when the heart enlarges, resulting in a decline in pumping efficiency?
Congestive Heart Failure (CHF)
What causes Pulmonary arterial hypertension?
Enlargement and potential failure of right ventricle
What is Arrythmias?
Variation from normal heart rhythm
What does ventricular fibrillation result from? What causes it and what is it a common cause of?
- A crippled conducting system
- Rapid, random firing of electrical impulses in the ventricles
- Common cause of cardiac arrest
What happens to the heart on about day 20-21?
Heart folds into thorax region
What day does the heart start pumping?
22
Are the earliest heart chambers unpaired or paired?
Unpaired
List the heart chambers within embryonic development from “head to tail”
Bulbus cordis, Ventricle, Atrium, Sinus Venosus
What does the Sinus-Venous become?
Smooth-walled part of right atrium, coronary sinus, and SA node
What does the Atrium become?
Ridged parts of right and left atria
What does the Ventricle become? What is this chamber known for?
Left ventricle; strongest pumping chamber
What does the Bulbus Cordis become?
Right ventricle
With the truncus arteriosus gives rise to the pulmonary trunk and first part of the aorta
What month is common for development of congenital heart defects?
Month 2
What is the most common congenital heart defect?
Ventricular septal defect
What are the 2 basic categories of defect?
- Inadequately oxygenated blood reaches body tissues
- Ventricles labor under increased workload
What can exercise help do for the heart?
- Increases strength of the heart
- Help clears fatty deposits in coronary arteries
As humans age, what changes happen to the heart?
- Hardening and thickening of heart valve cusps
- Decline in cardiac reserves
- Fibrosis of cardiac muscle
