Cardiovascular System - The Heart Flashcards
Define: Endothelium
simple squamous endothelium lining the inner aspect of the heart and blood vessels
Define: Tunica Intima
internal layer of the vessel wall
Define: Tunica Media
middle layer of the vessel wall
Define: Tunica Adventitia
Outer layer of the vessel wall
Define: Endocardium
inner heart layer
simple squamous epithelium
loose CT (subendothelial CT)
Purkinje Fibers (nuclei, intercalated disks)
closest to lumen/heart chamber
Define: Myocardium
Muscle Heart layer
Cardiac Muscle
Fibrous Skeleton
contains: contractile cardiocytes myoendocrine cardiocytes, nodal cardiocytes
Define: Epicardium
outer heart layer
Loose CT
Adipose Tissue
larger blood vessels, coronary arteries and veins
All muscle does:
movement → sliding filaments, actin and myosin
Arrangement of Skeletal and Cardiac Muscle
lined up to form striations
Arrangement of Smooth Muscle
no regular arrangement → no striations
Cardiac Muscle Organization
Sarcolemma with opening to T tubule
lateral component of intercalated disc
Z Line
T Tubule
Gap Junctions
Macula Adherens
Fascia Adherens
Transverse component of intercalated disc
Define: Intercalated Disks
Can think of structure as series of steps
desmosomes provide strength
gap junctions are there for electrical continuity
found in border between cells
What is different about Cardiac Muscle from Skeletal and Smooth Muscle?
it is striated
central nuclei
intercalated disk
branching myocytes
Ventricular Walls are thicker than…
atrial walls
Walls of the aorta are thicker than…
the walls of the vena cava
How does blood flow through the heart to the lungs?
Blood enters heart through right atria from vena cava → heart contracts → sends to right ventricle → heart contracts → blood moves to lungs
How does blood move from the lungs to the heart?
Blood flows from lungs through the pulmonary veins to the left atria → heart contracts → enters left ventricle → heart contracts → goes through aorta to rest of the body
Why is there more pressure in the arch of the aorta?
to send blood through the body
Where are valves located in the heart?
valves between atria and ventricles and arteries
valves prevent back flow
Define: Pericardium
external layer to outer epicardium
next to adipose tissue
What is the order of the layers of the heart from inner to outermost?
Endocardium
Myocardium
Epicardium
Pericardium
What are the 3 layers of the heart?
Endocardium
Myocardium
Epicardium
Define: Contractile Cardiocytes
contract to pump blood through the circulation
Define: Myoendocrine Cardiocytes
producing atrial natriuretic factor
Define: Nodal Cardiocytes
specialized to control the rhythmic contraction of the heart
located in the SA node at the superior vena cava → right atrium junction
located in the AV node → present under the endocardium of the interatrial and interventricular septa
Which has a thicker myocardium, the ventricle wall or the atrial wall?
the ventricle wall
Define: Fibrous Skeleton
collagen fibers that provide structure
function similarly to tendons → provide stable platform for contraction
muscle moves while fibrous skeleton stays still
Define: Valves
extensions of the fibrous skeleton covered in endothelium
3 layers (AV Valve) → ventricularis, fibrosa, spongiosa
Define: Ventricularis
Valve layer
dense irregular CT
Faces Ventricle
Define: Fibrosa
Valve Layer
Dense irregular CT; internal
continuous with fibrous skeleton
interior of valves → middle layer
Define: Spongiosa
valve layer
loose ct
faces atrium → more cells fewer fibers
Define: Chordae Tendinae
connect the valve to the papillary muscle to help regulate opening and closing
Heart Conducting System
- Coordinated Action
- impulses initiate in SA node → pacemaker cells
- transmitted to AV node (takes over as pacemaker if SA is damaged)
- further transmitted through bundle of His and Purkinje fibers to ventricular walls
Why do Purkinje Fibers stain lighter?
due to their glycogen content
What is the overall purpose of the circulatory system?
it delivers nutrients throughout an organism, and removes waste
The central part of the circulatory system is…
the heart
The heart has a specialized type of muscled called….
cardiac muscle
The cardiac muscle is connected to a…., which…
fibrous skeleton, which extends to form valves that regulate the direction of blood flow
A specialized network of electrical connections….
transmits signal for the SA node to the AV node to the ventricles
