Many roles of Vit B

Thiamine - B1 - coversion of pyruvate to acetyle co A for Krebs - beri beri, wernicke's encephelopathy, korsakoff's psychosis

Riboflavin - B2 - FADH - Electron acceptor -

Nicotinic acid - B3 - NADH - Electron acceptor - pellagra

Pantethonic acid - B5 - Coenzyme A

Pyridoxine - B6 - Transamination and amino acid metabolism - - dermatitis

Folic acid - B9 - tetrahydrofolate for nucleic acid synthesis - macrocytic anemia

Vitamin B12 - Cofactor for several enzymes  - pernicious anemia

Vitamin B - transamination

B6 - pyridoxal phosphate - transamination

Site- liver and kidney

Transaminase transfers amino group from an amino acid to alpha keto glutarate thereby converting amino acid to to alpha keto glutarate and alpha keto glutarate into amino acid.

Usually glutamate and alpha keto glutarate participate in this

Serine and threonine are metabolized by deamination. others are by transamination

Diagnostic enzymes

Myocardial infarction - Creatinine kinase (early), Aspartate transaminase, Lactate dehydrogenase
Pulmonary infarction - High LDH and normal CK and AST
Liver - alanine transaminase (ALT) and AST - aspartate trasaminase
Pancreas - Lipase and amylase
Muscle - same as heart + myoglobin which is a oxygen carrying protein in muscle
Prostate - acid phosphatase and prostate specific antigen
Biliary obstruction - Glutamyl transferase

Glycolysis

Rate limiting step - phosphofructo kinase
Fluoride inhibits enolase
Lactate dehydrogenase converts pyruvate to lactic acid in anerobic resp.

ATP
Steps 1 and 3 = - 2ATP
Steps 6 and 9 = + 4 ATP
Net "visible" ATP produced = 2.


NADPH
Reaction 5 is an oxidation where NAD⁺ removes 2 hydrogens and 2 electrons to produce NADH and H⁺. Since this reaction occurs twice, 2 NAD⁺ coenzymes are used.

Step	ATP (used -) (produced +)
1	-1
3	-1
5 - NADH to E.T.C to FAD = 2 step 5 used twice	2 x 2 = +4
6 used twice	1 x 2 = + 2
9 used twice	1 x 2 = + 2
NET	6 ATP

Base Pairing

Nucleotide - Nucleoside + phosphate group.

Adenine - thymine (uracil in RNA) - 2 bonds
Guanine - Cytosine - 3 bonds

Purines - A,G - Pure As Gold

Wobble effect - Multiple codons for same amino acid. These multiple codons mostly differ only in the third nucleotide. So,  a substitution on the third nucleotide will not cause any harm.

DNA is
Highly polar
hydrophilic
has major and minor groove - major groove is binding site for proteins

DNA Replication Animation - Best Video Ever

5' end - where the strand starts with phosphate group 3' end - where strand starts with carbon group. Helicase - unwinds DNA and splits DNA into two strands Topoisomerase - relieves supercoiling and tension from unwinding and winding. DNA gyrase - coils it back Please watch video - very thorough.

Genetic recombination

HIV VIRUS REPLICATION 3D

Brain - Overview

Procencephelon = Telencephelon (cerebrum) +  Diancephelon (epithalamus, thalamus, hypothalamus)

Mesencephelon - Midbrain

Rhombencephelon - cerebellum , pons, medulla oblongata

Brain stem - below cerebrum, infront of cerebellum - midbrain, pons, medulla oblngata

Limbic system - primitive centre deep inside temporal lobe.

Collection of nerve cell bodies in PNS - ganglia

Collection of nerve cell bodies in CNS - Nuclei

Brain Stem Model - Cerebral Nuclei

Muscle Spindles, Golgi tendon organ and reflexes

Muscle Spindle - Senses changes is muscle length

Intrafusal fibers run paralles to muscle fiers (extrafusal)

• nuclear bag fibres - fast changes
• nuclear chain - static changes

Activates alpha motor neuron

Innervated by gamma motor neuron

Has static and dyanamic sensors

Finer the movement, more the fibers

Stretch reflex - when a muscle is passively stretched, stretch reflex comes into play and contracts the muscle. effected by muscle spindle - monosynaptic - knee jerk reaction

Golgi tendon - Changes in muscle tension

Inhibits alpha motor neuron

Golgi tendon reflex - opposite of stretch reflex - when a muscle contracts, the reflex makes it relax - disynaptic - knife clasp reaction.

Flexor withdrawal reflex - pain - polysynaptic - ipsilateral flexion - contralateral extension

Fast twitch fibers and slow twitch fibers

Fast twitch - sudden burst of energy mainly by anaerobic (glycogen to lactic acid).  High myosin - ATPase activity and glycogen

Slow twitch - prolonged effort  using oxygen. - high capillaries, mitochondria, oxidative capacity

Myoglobin - oxygen binding protein in muscle.

Difference between all or none and fractionation

All or none - for a single muscle FIBRE or nerve FIBRE

If stimulus is inadequate -  no response.
If stimulus is adequate - maximum response

Fractionation - For a group of muscle fibres
If stimulus is low - few , thinner muscle fibers respond
If stimulus is high, more and more respond. Higher stimulus - thicker fibers

Difference between glycoproteins and proteoglycans

Proteo glycans - Disaccharide chains attached to a protein core. Rem - glycan refers to glucosamino glycans. More carbs than proteins. (95% to 55%) eg:heparin, heparan, keratan, dermatan, chondroitin

Glyco proteins - a protein with a carbohydrate attached to it. More protein to carb. eg: enzymes, hormones, cell membrane components

Difference between starch - glycogen - cellulose

Starch - 2 forms -
amylose - glucose polymer with unbranched chain
amylopectin - glucose polymer with alpha 1,4 linear and branches with 1,6 every 20 -30 glucose units


Glyocogen - similar to amylopectin - glucose polymer with alpha 1,4 linear linkage branches with 1,6 linkage every 12 glucose

Cellulose - glucose polymer with beta 1,4 linkage

Tongue

Development - 
Copula - hypobranchial eminence

Papilla 

Innervation 

Blood Supply


The tongue receives its blood supply primarily from the lingual artery, a branch of the external carotid artery and lingual veins which drain into internal jugular vein.

Thoracic cage

• Humans have 24 ribs (12 pairs). The second - seventh sets of ribs, known as "true ribs", are directly attached to the sternum through the costal cartilage.
• the first three (eighth, ninth, and tenth rib) have their cartilages attached to the cartilage of the rib above 
• the last two (eleventh rib and twelfth rib) are free at their anterior extremities and are termed floating ribs or vertebral ribs because they connect neither with the sternum nor with another rib. 

Kidney

Relations of Kidney -

the right kidney is related to the liver, duodenum, ascending colon or right colic flexure, and small intestine. 


 The left is related to the spleen, stomach, pancreas, descending colon or left colic flexure, and small intestine. Posteriorly, the kidneys are related to rib 12 and the diaphragm, psoas major, quadratus lumborum, and transversus abdominis

Histology of Digestive System

Villus - single layer of lamina propria covered by single layer of epithelium. Lamina propria contains blood vessels to absorb amino acids and simple sugar, lacteals to absorb fats in the form of chylomicrons and cholesterol.

Salivary gland histology

• The submandibular gland is a compound tubuloalveolar gland.
• It is surrounded by a capsule of moderately dense connective tissue, from which septa divide the gland into lobes and lobules.
• The secretory endpieces consist of a more or less spherical mass of cells called an acinus (pl. acini). 
• The cells of the acini appear triangular in sections, with their apex directed toward the lumen, and their base resting on a basement membrane. 
• They secrete their product in a merocrine fashion into the lumen. 
• Contractile cells called myoepithelial cells or basket cells lie between the basement membrane and the plasma membrane of the secretory cells. 
•  Myoepithelial cells posess many actin-containing microfilaments, which squeeze on the secretory cells and move their products toward the excretory ducts. They can sometimes be identified in standard histological preparations.
• Acini can be either serous or mucous.
•  The secretion of serous cells is thin, watery and proteinaceous. 
• Serous cells have a rounded nucleus and secretory granules in their cytoplasm. 
• They are joined near their apical surfaces by junctional complexes. 
• Mucous cells secrete a viscous, glycoprotein-rich product, which is stored as mucinogen granules.
•  The nuclei are typically flattened against the base of the cells (unless the cells have just discharged their contents, in which case they look more like serous cells). 
• Mucous cells typically look pale and empty in standard histological sections, because their granules are lost during preparation.
•  Its mucous acini are quite frequently capped with a serous demilune, a crescent of serous cells around one or more of their surfaces.

Types of Ducts

• There are three types of ducts in the submandibular gland: intercalated, secretory (aka striated) and excretory ducts.
•  Intercalated ducts are slender ducts continuous with the terminal acini, and lined with flat, spindle-shaped cells. They secrete bicarbonate ion into and absorb chloride ion from the acinar product. 
• Secretory ducts have eosinophilic cuboidal to columnar cells with basal striations. These result from infoldings of the basal membranes in which are found many mitochondria. Secretory ducts resorb sodium and secrete potassium
• Both intercalated and secretory ducts are found within the parenchyma of the gland and are therefore intralobular ducts.
• The largest ducts are the excretory ducts. They are found in the connective tissue septa, and are therefore interlobular ducts. 
• They ultimately connect with the oral cavity. 
• Their epithelium is variable, it can be simple cuboidal, stratified cuboidal, stratified columnar or pseudostratified. 
• Near the oral cavity, it becomes stratified squamous.
•  Excretory ducts do not change the secretory product.

Credit:http://www.courseweb.uottawa.ca/medicine-histology/english/gastrointestinal/Salivary.htm

Enamel Rods and crystals

Enamel rods are perpendicular to DEJ.
Inroganic crystals are parallel to body of rod and deviate towards tails.

Cells in Brain

Ependymal cells - line brain ventricles
Schwanna cells - around axon of nerve cell in peripheral nervous system and is derived from neural crest cells

Transitional Epithelium

Dome shaped cells - urinary bladder - ureters - superior urethra - prostate ducts

Blood Supply of Brain

Anterior communicating arteries - most common aneurysms- run on top

Middle - run on sides laterally - most common stroke

Posterior - run underneath or ventrally

Middle cerebral artery runs on lateral surface of cerebrum. - most common in stroke esp lenticulostriate nucleus

Note: Middle meningeal - most common sub dural hematoma and a branch of maxillary artery. one of three branches supplying meninges - anterior, middle and posterior,

Pain - Lateral Spino Thalamic tracts

Free nerve endings - A delta and C fibres.

 A delta - unmyelinated - fast - sharp

C - myelinated - slow - dull/burning

go to subsantia gelatinosa - (modulates sensory input acc gate control theory) in dorsal horn of spinal cord thru Lissauer's tracts 

Decussate and ascend contra laterally and reach thalamus mainly and other parts of brain.

Anatomy of a muscle cell

Epimysium - outisde entire muscle
perimysium- around bunch of muscle fibres
Endomysium - connective tissue sheath around each muscle fibre
Sarcolemma - plasma membrane of each muscle fibre.



each muscle fibre is made of a myofibrils.

Muscle Triad -  T - tubule which is an invagination of sarcolemma along wih 2 terminal cisternae ( they are just enlarged areas of sarcoplasmic reticulum storing calcium)

Sliding filament theory

Human skull

Face development

facial venous drainage

Pteryygoid Plexus

pituitary gland

Originates from - diencephelon

Umbilical blood supply

umbilical vein - placenta to liver  with oxy. blood - ligament teres of liver in adults

ductus venosus - venous shunt connects liver to Inf vena cava - ligamentum venosum in adults

formane ovale - opening btw left and rt. atria - bypasses pulm circulation - closes at birth and becomes fossa ovalis.

ductus arteriosis - between pulm trunk and aorta - bypasses pulm sirc - ligamentum arteriosum in adults

umbilical arteries - de0xy blood from fetus to placenta - lateral umbilical ligaments in adults

Trachea

 pseudostratified ciliated columnar epithelium cells

commences at the lower border of the larynx, level with the sixth cervical vertebra, and bifurcates into the primary bronchi at the vertebral level of thoracic vertebrae T4/5. at the sternal angle or angel of Louis

Dental pulp zones

Free nerve endings are in cell free zone below odontoblasts

Para nasal Sinus openings

above the superior concha and posterior to it - sphenoidal sinus opening
some posterior ethmoidal cells - superior meatus
maxillary sinus (hiatus semilunaris) , frontal sinus, anterior and middle ethmoidal air cells (ethmoidal bulla) - middle meatus
naso lacrimal duct opening - inferior meatus

Ganglia of cranial nerves

Facial nerve - geniculate ganglion
Smilunar / gasserian / trigemina ganglion - sensory nucleus of trigeminal nerve

parasympathetic ganglia of head and neck

CN 3 - Ciliary ganglia -  Preganglionic axons from theEdinger-Westphal nucleus travel along the oculomotor nerve and form synapses with these cells. Thepostganglionic axons run in the short ciliary nerves and innervate two eye muscles:

• the sphincter pupillae constricts the pupil, a movement known as Miosis. The opposite, Mydriasis, is the dilation of the pupil.
• the ciliaris muscle contracts, releasing tension on the Zonular Fibers, making the lens more convex, also known as accommodation.

CN 7 - Sub Mandibular ganglion - 

• Preganglionic parasympathetic fibers from the superior salivatory nucleus of the medulla oblongata, via the chorda tympani and lingual nerve, which synapse at the origin of:
• Postganglionic parasympathetic fibers to the oral mucosa and the submandibular and sublingual salivary glands.They are secretomotor to these glands.

CN - 7 Pterygo Palatine Ganglion - 

Pre ganglionic -  nervus intermedius (a part of the facial nerve) through the greater petrosal nerve.

Post ganglionic -  trigeminal nerve to the mucous membrane of the nose, soft palate, tonsils, uvula, roof of the mouth, upper lip and gums, and upper part of the pharynx. It also sends postganglionic parasympathetic fibers to the lacrimal nerve (a branch of the Ophthalmic nerve, also part of the trigeminal nerve) via the zygomatic nerve, a branch of the maxillary nerve (from the trigeminal nerve), which then arrives at the lacrimal gland.

CN 9 - Otic ganglion - lesser petrolar nerve from inferior salivatory nucleus to parotid gland from glosso pharyngeal nerve throught auriculo temporal.