Heart and Vascular Histology Flashcards
______ muscle cells are single, very long cylindrical, multinucleate cells with obvious striations
Skeletal
______ muscle cells are single, fusiform, uninucleate with nucleus centrally located, and without striations
Smooth
______ muscle cells are branching chains of cells that may be uni- or binucleate and they do have striations
Cardiac
Which of the following describes skeletal muscle cells?
A. Striated and voluntary
B. Striated and involuntary
C. Non-striated and voluntary
D. Non-striated and involuntary
A. Striated and voluntary
Which of the following describes cardiac muscle cells?
A. Striated and voluntary
B. Striated and involuntary
C. Non-striated and voluntary
D. Non-striated and involuntary
B. Striated and involuntary
Which of the following describes smooth muscle cells?
A. Striated and voluntary
B. Striated and involuntary
C. Non-striated and voluntary
D. Non-striated and involuntary
D. Non-striated and involuntary
Describe the type of contractions exhibited by smooth muscle
Produces continuous contractions of low force
Rhythmic contraction that is inherent, but responsive to ANS
Skeletal and smooth muscle both have actin and myosin involved in their contraction, but what makes smooth muscle different?
They are not arranged in sarcomeres, so they lack longitudinal arrangement of contractile proteins. Instead, actin and myosin bundles criss-cross the cell and are anchored at focal densities
Tension produced is transmitted through the densities to the membrane; cells contract as one unit and assume a globular shape.
The signaling mechanism also differs
_____ Muscle cells are short, branched, and y-shaped. They are associated with extensive capillaries.
Cardiac
Cardiac muscle cells are associated with _______ ______ which are transverse junctions at the ends of cells that allow passage of electrical current
Intercalated discs
_______ cells are modified cardiac muscle cells that act as the pacemaker for the heart
Purkinje
What are the 2 layers of the pericardium?
Fibrous pericardium
Serous pericardium
The _______ pericardium is the outer covering of dense connective tissue
Fibrous
The serous pericardium consists of the following:
_______ layer = lines the inner surface of the fibrous pericardium
_______ layer = covers the outer surface of the heart
_______ ______ = space between the above 2 layers
Parietal
Visceral (epicardium)
Pericardial cavity
Which of the following is referred to as the epicardium?
A. Fibrous pericardium
B. Parietal layer of serous pericardium
C. Visceral layer of serous pericardium
D. Pericardial cavity
C. Visceral layer of serous pericardium
What are the 2 major layers of the heart wall?
Epicardium = outermost layer
Myocardium = thickest layer of the heart
Endocardium = inner layer
Describe the histological composition of the epicardium
Dense fibrocollagenous CT with elastic fibers, lined with mesothelium
Branches of coronary arteries are embedded in adipose tissue
The myocardium is the thickest layer of the herat. What are the 3 major cell types associated with the myocardium?
Cardiomyocytes (contractile)
Nodal cardiomyocytes (SA and AV nodes)
Myoendocrine cardiomyocytes (contain atrial granules)
Which layer of heart tissue is lined with mesothelium? What is mesothelium?
Epicardium; mesothelium is simple squamous epithelium that is associated with a serous membrane
Myocardium is characterized by:
________ due to sarcomere arrangement
________ discs
_______ t-tubule system
Mitochondria
_______ and _______ granules
Striations
Intercalated
Diad
Lipofuscin; atrial
Compare/contrast the t-tubule systems in cardiac vs. skeletal muscle
Cardiac = diad t-tubule system
Skeletal = triad t-tubule system
Intercalated discs are specialized interdigitating junctions between cardiomyocytes found at sites where cells meet end-to-end. They always coincide with _______
Z lines
What is the function of intercalated discs?
Bind cells, transmit forces of contraction, and allow the spread of excitation
Intercalated discs have varying membrane-membrane contacts based on 2 regions: transverse (perpendicular) and longitudinal (parallel).
What are the 3 types of membrane-to-membrane contacts exhibited by intercalated discs? Which region are these associated with?
2 in transverse region:
Fascia adherens
Desmosomes
1 in longitudinal region:
Gap (nexus) junctions
Intercalated discs have 3 types of membrane-membrane contacts. 2 in transverse region: fascia adherens and desmosomes; and 1 in longitudinal region: gap (nexus) junctions.
Which type of membrane-membrane contact transmits contractile forces between cells and is the most predominate?
Fascia adherens
Intercalated discs have 3 types of membrane-membrane contacts. 2 in transverse region: fascia adherens and desmosomes; and 1 in longitudinal region: gap (nexus) junctions.
Which type is found at sites of low electrical resistance and allows excitation to pass between cells?
Gap (nexus) junctions
Intercalated discs have 3 types of membrane-membrane contacts. 2 in transverse region: fascia adherens and desmosomes; and 1 in longitudinal region: gap (nexus) junctions.
Which type contains actin filaments at the ends of terminal sarcomeres which insert into junction?
Fascia adherens
Intercalated discs have 3 types of membrane-membrane contacts. 2 in transverse region: fascia adherens and desmosomes; and 1 in longitudinal region: gap (nexus) junctions.
Which type provides the anchorage for the intermediate filaments of the cytoskeleton?
Desmosomes
Describe the components of a diad T-tubule system associated with cardiac muscle cells
Diad = 1 T-tubule + 1 SR cisterna
Diad t-tubules are fingerlike invaginations of the ________ and are found at the ___-lines.
They permit uniform contraction of _____ within a single cardiomyocyte
Sarcolemma; Z
Myofibrils
______ granules are small bodies that accumulate ith age in stable non-dividing cells like cardiomyocytes
Lipofuscin
Lipofuscin granules are small bodies that accumulate ith age in stable non-dividing cells like cardiomyocytes. They contain material derived from what?
Residual bodies after lysosomal digestion
What important biological molecule is contained within atrial granules?
Atrial natriuretic factor - which targets the kidneys to decrease Na+ and H2O retention, thus increasing urine output
Important because it gives your heart some endocrine function!
About 600 atrial granules are contained within each ________ cell, although smaller quantities are found in the _____ atrium and ventricles
Myoendocrine; left
The endocardium is made up of what 2 major components?
Endothelium
Thin layer of loose CT
What type of endothelium is found in the endocardium?
Simple squamous
The thickness of the endocardium differs in ventricles vs. atria. The ventricular endocardium has a ________ layer composed of a thin layer of CT with smooth muscle as well as purkinje fibers
Subendocardial