Histology Practical Flashcards
Formation of new cartilage from existing perichondrium
Appositional growth
Growth within the cartilage mass
-chondrocytes that are still capable of cell division form isogenous groups (cell nest)
Interstitial growth
Found in the nose, larynx, respiratory track, costal ribs, and articular cartilage of synovial joints
Hyaline cartilage
Appears more opaque and yellow than hyaline cartilage
Elastic Cartilage
Has larger and more abundant chondrocytes and less matrix than yaline cartilage
Elastic cartilage
Which types of cartilage have NO perichondrium?
Fibrocartilage and Articular Hyaline cartilage
Has cells in lacunae alligned in rows
Fibrocartilage
Unlike other cartilage types, fibrocartilage matrix is made up of a dense network of
Collagen I (acidophilic matrix)
Cartilage is nourished via
Diffusion
Bone is nourished via
Blood vessels
In an H and E stain, cartilage stains
Basophilic (blue)
In an H and E stain, bone stains
Eosinophilic (red)
What are the three connective tissue layers surrounding peripheral nerves?
Endoneurium, perineurium, epineurium
Surrounds a single axon and its Schwann cell covering
Endoneurium
What type of collagen does the endoneurium contain?
Type III
1-3 cell layers thick of dense CT which are contractile and contian actin
Perineurium
Surrounds individual axon bundles of fascicles to form a semipermeable barrier
Perineurium
Surrounds many axon bundles and fills the spaces between them
Epineurium
Consists of dense irregular CT and contains blood vessels that supply the nerves
Epineurium
In unmeylinated axons in the PNS, Schwann cells encase the axons but do not
Wrap around them to form a myelin sheeth
Cytoplasm of the Schwann cell can be seen around the
Individual unmyleinated axon in the PNS
Unmyelinated axons in the CNS are not surrounded by
Oligodendrocytes
The only way to tell the location of a myelinated axon is to look at the
Unmyelinated ones
What are some differences between PNS fibers and Smooth muscle?
PNA has uneven distribution of various types of nuclei and very wavy and frothy
-blood vessels usually not seen
A cluster of nerve cells located in the peripheral nervous system
Ganglia
Sensory neurons are classified as
Pseudounipolar
Have large spherical neurons and a centrally located nucleus
Sensory ganglia
Have nucleus at one side of the neuron, few satellite cells at periphery of neurons and few nerve fibers around the nucleus
Autonomic (sypathetic) Ganglion
Have many satellite cells surrounding the cell body
Sensory ganglia
Increases surface area of dendrite
Dendrite spine
Striated with peripheral nuclei and surrounded by a basal lamina and satellite cells
Skeletal muscle
The orderly arrangement of actin and myosin in a sarcomere are responsible for the
Banding pattern observed under EM and LM
Visible ONLY at the EM level
Myofilaments
Made up of many myofilaments and surrounded by a sarcoplasmic reticulum
Myofibril
The cross section of the myofibril is visible at the LM level and it appears as
Dots
The longitudinal section of a myofilament is visible only at the
EM level
Made up of many myofibrils and surrounded by an endomysium
Myofiber
Made up of many myofibers and surrounded by a perimysium
Fascicle
Made up of many fascicles and surrounded by epimysium
Muscle
Surrounds each myofibers
Endomysium
Surrounds each fascicle
Perimysium
Surrounds many fascicles
Epimysium
Myofibrils are made up of many myofilaments and surrounded by the
Sarcoplasmic reticulum
Made up of actin (thin filaments) and myosin (thick filaments) arranged in an orderly manner
Myofilaments
A sarcomere, the contractile unit of muscle, extends from
Z-disc to Z-disc
Does not change shape during contractin
A band
Extends from the Z line to the M line and is closely associated with myosin
Titin
Generates passive tension through elastic tension when the sarcomere is stretched
Titin
Titin prevents
Overstretching
Extends from the Z band along the length of the actin filament
Nebulin
Acts as a template for the regulation of filament length
Nebulin
Intermediate filament which encircles the Z disk of each sarcomere and extends from one myofibril to the other and is anchored to the sarcolemma
Desmin
Facilitates the coordinated contraction of individual myofibrils by holding adjacent myofibrils together forming a supportive latticework and linking them to the sarcolemma
Desmin
Surrounded by a cell membrane (sarcolemma) and has peripheral nuclei
Muscle cell
Each muscle cell is surrounded by a thin layer of CT called the
Epimysium
Thicker in skeletal muscle than in peripheral nerves
Perineurium at myotendon junction
Located at every A-I junction
T-tubule
Provides rapid transmission of the surface membrane excitation
T-tubule
SER expansions that release and store Ca2+ via a voltage sensitive Ca2+ channel
Terminal Cisterna
The T-tubule and 2 terminal cisterna
Triad
In a myoneural junction, each nerve branch innervates a single
Muscle fiber
Striated, short, branched fibers with 1 or 2 centrally located nuclei
Cardiac Muscle
CT between cells of cardiac muscle is greater than in
-not as organized as skeletal muscle
Skeletal muscle
Cardiac muscle cells have T-tubules at
-EXCEPT when there is an intercalated disc
Z-lines
Intercalated discs are specific cell to cell boundaries in cardiac muscle and contain
- ) Fasciae adherentes (transverse component)
- ) Desmosomes (Lateral component)
- ) Gap Junctions (Lateral component)
In a cross section, cardiac muscle cells will exhibit a
Variety of shapes
Fascia adherens (transverse component) is made up of
Actin filaments
Spot desmosomes are made up of
Intermediate filaments
Modified myofibers found in clusters beneath the endocardium lining the two sides of the interventricular septum
Purkinje fibers
Large cells with pale cytoplasm due to glycogen content
-contain intercalated discs
Purkinje fibers
Function to conduct impulses to the ventricular myocytes
Purkinje fibers
Spindle shaped tapering cell with one centrally located nuclei and indistinguishable borders
Smooth muscle
Located at the ends of nucleus in smoothmuscle
Perinuclear organelles
Smooth muscles control involuntarily controlled contractions as sheets or bundles or cells due to
Gap Junctions
Invaginations of the plasma membrane in smooth mucle are called
Caveolae
Smooth muscle has no T-tubules and an underdeveloped SR. It contains cytoplasmic dense bodies that act as
Z discs (myofilament attachment sites)
Smooth muscle cells are surrounded by basallamina except at
Gap junctions
Found in sheets with very little CT between cells
Smooth muscle
Nerve bundle between 2 muscle layers
Myenteric Plexus
