Basic Histology Part II Flashcards
What is adipose tissue?
Fat tissue found throughout the body among soft tissues, marrow cavities and beneath the skin in certain areas
Cells include fibroblasts and adipocytes
What cells are found in red bone marrow?
Proerythroblast, hemocytoblast, thromboblast and adipose
Precursor cells
What is the Intercellular substance in red bone marrow?
Thin reticular fibers
What does red bone marrow produce?
Erythrocytes, leukocytes, lymphocytes, monocytes, platelets/thrombocytes and plasma cells
Where is lymphatic tissue found?
In the sinus and lymphoid nodes
What cells are found in lymphatic tissue?
Leukocytes, lymphocytes, macrophages and plasma cells
What is blood and what does it transport?
Fluid derived from bone marrow and lymphoid tissues
Transports cellular nutrients, oxygen, CO2 and metabolites
What are platelets essential for and why is it so important for us to know patient clotting time?
Essential for clotting. We must know patients clotting time before treating them so we know if and when they will stop bleeding
What is the purpose of plasma?
Carries plasma proteins, antibodies, blood cells and metabolites.
Platelet Rich plasma promotes bone graft healing
What is serum?
Plasma minus clotting proteins
What are polymorphonucleocytes?
Type of white blood cell.
Mature granulocyte
Examples include neutrophils, basophils and eosinophils
What is the difference between leukocytes and lymphocytes?
Both are white blood cells and function in immunity. All lymphocytes are leukocytes but not all leukocytes are lymphocytes.
There are many types of leukocytes, lymphocytes are agranular leukocytes. Lymphocytes include NK cells, T cells and B cells
What is the difference between monocytes and macrophages?
Monocytes are the largest type of white blood cell and play a big role in adaptive immunity. Macrophages are monocytes that have migrated from the bloodstream into any tissue in the body
Macrophages are also fixed in tissues where monocytes circulate
What is cartilage?
Specialized connective tissue made of a high amount of amorphous substance
What is the Intercellular substance in cartilage?
Collagen and elastin
What are the cells of cartilage?
Chondroblasts and chondrocytes. Chondrocytes occupy lacuna spaces in Intercellular substance
What is the perichondrium?
Non-calcified, fibrous connective tissue sheath that covers cartilage and contains blood vessels
Always associated with hyaline cartilage
What is permanent cartilage?
Does not ossify, nutrients are supplied by the perichondrium
What is hyaline cartilage
Blue – white , Glassy translucent and contains collagen fibers
Found in the larynx, nose, trachea, ends of long bones and articular capsule

What is fibrous cartilage?
White and contains thick compact collagen fibers. Never found alone, merges with hyaline cartilage.
Found at the end of “healing bone fractures”
No perichondrium
What is elastic cartilage?
Yellow, more flexible and contains elastin fibers
Found in the eustachian tubes, external ear, epiglottis and parts of the larynx
What is temporary cartilage?
Makes up the skeleton of an embryo and the ends of long bones. Is replaced by bone
What is bone matrix/osteoid calcified by?
Calcium hydroxyapatite
What are bone cells called?
Osteocytes
Occupy lacunae with canaliculi
What is the difference between osteoblasts and osteoclasts?
Osteoblasts build bone and osteoclasts resorb and create spaces for new blood vessel formation
What is the composition of bone?
55% organic – collagen
45% in organic – minerals
What are muscle tissue cells called?
Myoblasts
Form muscle myofilaments
Properties of muscle tissue
Contractibility
Functions to move the body
What are the smallest contractile elements composed of myofilaments
Myofibrils
What are the two types of myofilaments that compose myofibrils
Actin and myosin
Describe myosin fibers
Thicker band with cross bridges on the ends
Describe actin fibers
Thinner band, active sites on the opposite end
What is the Sarcoplasmic reticulum?
This is what allows muscles to contract
System of tubes closely approximated with myofibrils that communicates nerve impulses to activate the calcium pumps

What is facia?
Sheets of connective tissue beneath the skin that attach to, stabilize, and clothes and separate muscles and other internal organs
What is a fascicle?
Bundle of skeletal muscle fibers surrounded by CT
What is a fasciculus?
Small bundle of nerve, muscle or tendon fibers
What is an endomysium?
CT covering each individual myofiber/muscle cell
What is the perimysium?
CT covering a group of muscle fibers or fascicle
What is the epimysium?
CT sheath surrounding a skeletal muscle
Features of smooth muscle tissue
Mix of walls of blood vessels, stomach and digestive tract
Involuntary contractions- Peristalsis
Features of cardiac muscle tissue
Involuntary
Controls the rhythmic beating of the heart
Single impulse from autonomic nervous system will cause all cells in a section to contract
Features of skeletal muscle tissue
Voluntary muscle contractions
Innervated by peripheral nervous system
Contractions are rapid and voluntary
What initiates muscle contractions and how are they transmitted?
Initiated by the brain and transmitted by acetylcholine synapses
Causes Sarcoplasmicreticulum to release calcium ions stimulating myofilaments to pull together the contracting muscle
What is a sarcomere?
Contractile unit of myofibrils
Relaxed sarcomere
Two portions
Actin on either side of Myosin
 myosin in center of the sarcomere
Contracted sarcomere
During contraction myosin projections interact with actin and pull it into the center of the sarcomere
What is hypertrophy?
Muscle cells enlarging
Heavy resistance increases skeletal muscle size but does not increase the number of muscle cells
What causes muscle pain?
Lactic acid buildup which is a product of oxidation
Anaerobic production of ATP
What is the difference between muscle spasm and muscle cramps?
Muscle spasms are sudden involuntary contractions that may cause pain
Muscle cramps are painful spasmodic muscular contractions
What are mild clonic spasms?
Hiccups
What is tic douloureux
Trigeminal neuralgia. Excruciating facial/dental pain involving the trigeminal nerve of the lower face and jaw
What are tonic spasms?
Sustained contraction due to rabies or tetanus
How does muscle tissue repair itself?
With severe injury muscle tissue repairs with scar tissue
With minor injury it heals without scarring and does not affect muscles ability to stretch
Two main divisions of the nervous system
Central nervous system and peripheral nervous system
What is included in the central nervous system?
Brain and spinal cord. White matter and gray matter
 What are the two branches of the peripheral nervous system
Autonomic nervous system and somatic nervous system
What is the peripheral nervous system composed of?
Made up of ganglia
ganglia and peripheral nerves are outside of the CNS and all found in pairs
Cells are very tough and maybe myelinated
Dental nerve or core fasciculus
What are the dental nerve or core fasciculus?
Mantle bundles and core bundles
Mantle bundles
Near the outer surface and innervate mandibular Molars
Core bundles
Deep, innervate the interior mandible
Divisions of the autonomic nervous system
Sympathetic and parasympathetic
Regulates Involuntary nerve impulses
Sympathetic nervous system
Fight or flight response
 Stimulates adrenaline production and inhibits salvation
Parasympathetic
Rest or digest response
Inhibit adrenaline and stimulates salvation
Somatic nervous system
Regulates voluntary nerve impulses, all skeletal muscles including those of the head and neck
Features of nerve tissue
Highly organized
Pick up stimuli
Cannot reproduce and have limited repairative properties
Conductivity
What is the difference between an anomaly and a defect?
Cleft palate versus cells that become atypical via trauma, bacterial infection, virus etc.
What are neurons?
Nerve cells- largest cells in the body
One cell body with processes
Contain neurofibril‘s, Nissl bodies, Golgi and mitochondria
What is a neuron process?
Nerve fibers; axons and dendrites
What are axons?
Conduction of impulses away from the neuron
Branch at termination points of forming synapses with other dendrites
What are dendrites?
Thread like extensions of neuroplasm that branch into tree like processes and compose the largest receptive surface of a neuron
Receive stimuli from other nerves and or receptor organs
What are the three types of neurons?
Sensory, interneuron and motor
What are sensory neurons?
Afferent, carries impulses to the brain
What are interneurons?
In the brain or spinal cord, carries impulses to motor neurons
What are motor neurons?
Efferent, carries impulses to muscles
What is a neurolemma?
Sheath of living cells that cover myelinated nerve fibers and contain Schwann cells
What are Schwann cells
Found in the neurolemma, produces the myelin sheath
What is the myelin sheath
Insulates axons nerve fibers and enables fast impulse conduction
What are nodes of Ranvier
Two successive Schwann cells a butt on the nerve fiber
Enables rapid impulse conduction
Unipolar neurons
Have one axon and no dendrite
Axon branches into two parts, one branch acting as a functional dendrite to send impulses to the neuron. Other branch transmits impulses away from the neuron
ie. Cerebral cortex/cerebellum
Bipolar neurons
One axon and one dendrite, two processes
Impulses conducted from the dendrite to neuron than along the axon
ie. Retina, inner ear, olfactory mucous membranes
Multipolar neurons
One axon and several dendrites
Motor neurons have a long axon and short dendrites
Sensory neurons have a short axon and long dendrites
 what is the neurolemma?
Nerve membrane covering
Describe resting state with resting potential
Sodium concentration is highest outside of the neurolemma
Potassium concentration highest on the inside of the neurolemma
Membrane has a positive charge outside and negative charge inside
Depolarization with action potential
Occurs when an impulse is sent
Outer membrane surface momentarily reconfigures
Calcium ions released from binding sites
Sodium ions rush into the axoplasm with potassium moving out
Membrane has depolarized
What is the refractory period
Absolute: nerve fiber cannot conduct
Relative: nerve fiber will conduct if the next impulse is stronger than the initial
Repolarization
Restores resting state
Occurs behind depolarization
Sodium ions rush back outside the neurilemma and potassium ions rush back inside
Calcium ions return to binding sites on membrane and resting state with resting potential is restored
