Exam 2 Flashcards
What are the three types of muscle
Skeletal, Caridac, Smooth
Skeletal Muscle
Structure
Structure: Myofiber, myfibril, myofilament
Cardiac Muscle
Structure
Structure: Myofiber, myfibril, myofilament
Myofiber
A cell that contains many myofibrils.
surrounded in an endomysium (which is connective tissue).
CT trend!!
Epi - Always the most outer
Peri - The middle
Endo - The most inner
Sarcoplasm
The cytoplasm of striated muscle cells
Myofibrils
Made up of many: Sarcomeres
Coated by Sarcopplamic reticulum & T tubules
Make up: Myofibers
T tubules
T-tubules lie at the boundary of the A and I bands (so there are 2 tubules per sarcomere in skeletal muscle)
Will be found on the Z disk in cardiac muscle
Smooth muscle doesn’t have T tubules.
- Continuous with the plasma membrane
Sarcoplasmic reticulum
Stores Ca2+
When a sarcomere is contracted what is not visible
A and I bands
What are the three fiber types
Type 1 : SLOW-twitch just oxidative. Small size highest mitochondrial density
Type 2a: FAST-twitch oxidative and glycolytic. Medium size many mitochondria
Type 2b: FAST-twitch just glycolytic. Large and pale low mitochondrial density.
Titin
Larges protein in the body acts like a spring. It resists both compression and extension
Sequence of Events for Contraction
1) Nerve impluse travels down axon
2) Acetylcholine is released into the synaptic cleft, which depolarizes the sarcolemma
3) Voltage gated Na+ channels open and Na+ enters the muscle cell
4) T-tubule depolarizes
5) Voltage sensor prot
6) Ca2+ released from Sarcoplamic reiculum
7) Ca2+ binds to the TnC subunit of troponin allowing myosin to bind to actin
8) Actomyosin cross-bridge cycle is initiated
9) Ca2+ is re-sequestred to relax muscle
Thing Filament
Made up of : Filamentous ACTIN, tropomysin and troponin.
In the presence o calcium the topnin/tropomyosin complex moves on the actin filament so that myosin can bind to actin and begin contraction.
Tropomyosin
An elongate protein
Troponin complex
Made up of 3 subunits Tn-I, Tn-T, Tn-C
Tn-C binds to calcium
Tn-I prevents myosin from binding to tropomysin without Ca2+
Tn-T binds to tropomyosin
Cross-Bridge Cycle
1) Release state - ATP binds
2) Cocking state - ATP hydrolyzes
3) Binding state - ADP + Pi (still bound)
4) Power stroke - Pi released
5) Release state - ADP/ATP exchange
Three main branches of the peripheral nervous system
Autonomic: Sensory neurons, Moto neurons (voluntary: Skeletal muscle)
Somatic: Sensory neurons (visceral afferents) , Motor neurons (involuntary: Smooth and cardiac muscle, glands)
Enteric : Sensory neurons (entire GI tract) Motor neurons (smooth muscle, glands), Function (regulates GI activities, independent of CNS)
Nissl Bodies
Rough ER in neurons
Acetylcholinesterase
Used to degrade acetylcholine and prevent continued stimulation
Neuroglia
Different for CNS* / PNS
Supportive cell type in the NS
- More abundent than neurons
CNS : Astrocytes - Oligodendrocytes - support nonmyelinated and myelinated nerves Microglia - Ependymal cell -
PNS
Schwann cells - Myelinate or enclose unmyelinated axons
Satellite cells - Surround cell bodies in ganglia
Oligodendrocytes
Make the buelin sheath of the CNS
Can myelinate multiple neurons ( unlike schwann cells)
Synthesizes myelin proteins: PLP, MOG, OMgp
Blood-Brain Barrier
Protect the brain by preventing harmful stuff from getting in.
Tight junctions create the BBB and are supported by astrocytes
Schwann cell
Only found in the PNS
Function :
Myelinate myelinated axons or Support unmyelinated axons but do not insulate them.
Composed of >80% lipids
Pacinian corpuscle
Detects pressure and vibration. Associated with myelinated axon
Meissner corpuscle
Detects fine touch. Found in the dermal papillae that are associated with myelinated axons.
Regeneration of Peripheral Nerves (steps)
1) Nerve fiber and myelin sheath degenerate
2) Macrophages clear debri
3) Schwann cells form cords of Bunger
4) Axonal sprouts follow cord of Bunger and eventually reach the atrophied muscle
Anterograde Transport
Movement away from the Soma
Mediated by kinesin
Retrograde transport
Movement toward the Soma
Mediated by dynein
Motor unit
All the myofibers innervated by one motor neuron.
Each myofiber is innervated by only one axon terminous and one neuromuscular junction.
What type of muscle cell communicates via gap junction?
Cardiac and Smooth muscle
What does Osmium retain?
Lipids
Ganglion
When there are nerve cell bodies outside the central nervous system
Ganglion*
When there are nerve cell bodies outside the central nervous system
What is blood made up of
Plasma 55%, Cells 45%
What are the different kinds of capillaries
Continuous, Fenestrated, Sinusoidal
What makes up Plasma
7% Proteins: Albumins, Globulins, Fibrinogen, and others.
- 5% Water
- 5% Other solutes
Platelets
Sort of a cell but don’t have a nucleus.
Function - Clot formation
Granules - Alpha (clotting factors), Dense Core (serotonin)
Hepatic portal vein
Renal capillaries
Artery -> Capillary -> Vein -> Capillary -> Vein
Artery -> Capillary -> Artery -> Capillary -> Vein
Intercalated Disc
Transverse component:
- Fascia adherens
- Desmosomes
Lateral components:
- Gap junctions
- Desmosomes
What are the three Blood Vessels
Arteries - Blood away from heart
Capillaries - site of gas, nutrient and waste transfer
Veins - Blood to the heart
Endothelial Cell
Functions:
Different Arteries
Elastic: Aorta, subclavian, pulmonary arteries. Resistant to large pressure. Elastic fibers allow stretching for pressure, and collagen fibers restrict too much stretching.
Muscular: All arteries other arteries. Artery wall is predominately made T. media composed of smooth muscle
Arterioles: Regulate Blood pressure
Different parts of Arteries
Tunica Intima, Tunica Media, Tunica Adventitia
Tunica Intima
Made up of:
- Lining endothelium with its basement membrane
- Subendothelial Layer (Loose CT with few smooth muscle cells)
- Internal Elastic Lamina (Elastic CT sheet)
Most prominent in muscular artery type
No capillaries
Tunica Media
A reinforced wall
Made up of: Smooth muscle cells
No capillaries
Tunica Adventitia
Made up of: Dense Irregular CT & Type 1 Collagen
Is connective tissue
Arterioles
Function: Regulates flow to capillaries through vasodilation & vasconstriction
Arterioles
Function: Regulates flow to capillaries through vasodilation & vasconstriction
Primary regulator of systemic blood pressure.
Capillaries
The smallest vessels
- Wide enough for a single RBC
- Site of gas exchange
Three types of Capillaries
and describe them
Continuous: Complete endothelium, and complete basal lamina
- Found in CNS, lung, CT, muscle tissue
- Most predominant
Fenestrated: Fenestrated endothelium, but complete basal lamina
- Found in kidney, endocrine, intestines
- Bullk transfer
Sinusoids: Incomplete endothelium, and basal lamina
- Found in Liver, Bone marrow, and Spleen
Venules
Found after capillaries and can be High endothelial venules, muscular venules, and Venules.
Extravasation
1) Rolling and attachment
2) Adhesion
3) Transendothelial migration
HEV are highly attuned to let extravasation to occur
Veins
Tunica Intima
- No internal elastic lamina (except for large veins)
Tunica Media (Smooth Muscle) - Muscular contraction generates pressure
Tunica Adventitia (CT & SM)
- Most prominent layer
- Smooth Muscle
Parts of the Innate Immunity
1) Barriers
2) Complement system
3) Cells
- Blood leukocytes
- Granulocytes: Neutrophils, Eosinophils, Basophils
- Agranulocytes: Monocytes, Natural Killer cellls
- Connective tissue
- Resident cells: Macrophages, Mast cells
- Transient cells: blood leukocytes, dendritic cells
4) Inflammation
PAMPs
Pathogen-associated molecular patterns (PAMPs) are recognized by PRR’s. PAMP recognition receptors.
Toll-like receptors (TLRs) are a type of PRR
PRRs bind to PAMPs and initiate phagocytosis.
B cells
Produced in the Bone Marrow
Become: Plasma cells, memory cells, and regulatory B cells
IgA secreted into secretions (tears)
IgG main antibody
T cells
Produced in Thymus
Expresses one T cell receptor (TCR)
TCR’s only bind to epitopes when presented by MHC proteins
T helper cells (types)
T helper 1 (Th1) activate macrophages
Th2 activate B cells to mature to form plasma cells or memory cells
Cytolytic T cells
Tc cells and NK cells recognize and kill infected cells
Antigen presentation
1) Phagocytosis of antigen
2) Degradation of antigen and binding of antigenic peptides to MHC 2
3) Presentation of epitope bound to MHC 2 to TCR
Purpose of the Lymph
To filter lymph and blood in order to produce lymphocytes
Primary, Secondary lymphatic organs
Primary: Bone, Thymus
Secondary: Lymph nodes, lymphatic nodules (MALT), diffuse lymphatic tissue, slpeen
Lymph formation pathway
Blood plasma -> Fluid in CT -> Tissue fluid -> Fluid in lymphatic vessels -> Lymph
Structure of Lymph node
Cortex - Network of reticular fibers (type 3 collagen)
Outer cortex - Lymphatic nodules with germinal centers
- Germinal center is rich in B cells
Inner cortex - Enriched in T cells
Meduallry cords - Enriched in plasma cells
Medullary sinuses - Enriched in phagocytes
BALT
Has to do with airways and is big on IgA
Secretory IgA pathway
dIgA (dimer IgA) binds to pIgR (polymetric immunoglobulin receptor) is then endocytoesd cleaved then exocytoesed as sIgA (secretory IgA)
How do mature effector T cells leave the Thymus
Through HEV’s
Cords
In the lymph node cords are extensions of cortex and contain plasma cells.
Germinal centers
Sites of B cell production and selection
Purkinje Fibers
Large, Pale staining cells that contain large amounts of glycogen.
Endocardium
Made up of: Inner layer of endothelium, layer of CT, and subendocardial layer containing purkinje fibers
Ameloblasts
Form the inner enamel epithelium.
Synthesizes Enamel
When tooth erupts from gum ameloblasts degenerate
Odontoblasts
Synthesize Dentin
Odontoblasts
Synthesize Dentin
Line the pulp cavity
Different kinds of tonge papillea
Filliform, Foliate, Fungoiform, Circumvallate
Filiform is the only kind without taste buds
What are the three salivary glands
Sublingual, Submandibular, and Parotid
Sublingual - Mucus secreting
Subman. - Mucus and Serous secreting
Parotid - Serous secreting
Taste buds are compsed of
Neuroepithelial cells (which detect taste), supporting, and basal stem cells.
Basal cells divide into both neuroepithelial and supporting cells.
Salivary ducts pathway
Secretions from the salivary glands enter intercalated ducts
1) Intercalated ducts (serete K+ and HCO3 absorb Na+)
2) Striated (intraobular) ducts (secrete HCO3 absorb Cl-)
3) Excretory (interlobular) ducts.
Four tissue layers of Alimentary canal
Mucosa,
Submucosa,
Muscularis externa, Serosa/Adventitia.
Chief cell
Secretes digestive enzymes (like pepsinogen)
Parietal Cell
Secretes intrinsic factor, which is needed for vit. B12 absorbtion and transport of HCl into the stomach
What are the five primary cell types in the simple columnar epithelium of the intestine
Goblet cells Enterocytes Stem cells Enteroendocrine cells Paneth cells
Paneth cells
Found in: Crypts
Function: Secrete antimicrobial agents (alpha-defensins and lysozume)
