Medical Education for Students

Gross Specimens General Pathology (50 specimens)

2012-08-02T12:55:00.000+05:00

A competent doctor should good at appreciating the nature of deformity or abnormality in gross structures as well as in microscopy. Here are some formaline preserved specimen in glass jars. These pics are captured at AIMC pathology lab, Lahore Pakistan...

Medical Mnemonics

2012-07-28T14:26:00.001+05:00

Medical Mnemonics..... Medical students often find it difficult to memorize some confusing terms in the course of there studies. Here is an effort to assist and make the students able to cope with such difficulties. You may find it useful......

Anatomy mnemonics for Medical students

Anatomy mnemonics on medical education for students

Anatomy mnemonics on medical education

Anatomy mnemonics

Pathology Slides

2012-04-19T07:56:00.000+05:00

How to identify pathology slides in the laboratory.

P.vivax (trophozoite).jpg

P.vivax.jpg

RBCs in urine.jpg

ascaris lumbricoides.jpg

ascaris lumbricoides1.jpg

calcified hydatid cyst.jpg

calcified hydatid cyst1.jpg

candida in urine.jpg

candida in urine1.jpg

egg ancylostoma doudenale in stool.jpg

egg ancylostoma doudenale.jpg

egg ascaris lumbricoides.jpg

egg ascaris lumbricoides1.jpg

epithelial cells in urine..jpg

epithelial cells in urine.jpg

uric acid crystals in urine.jpg

uric acid crystals in urine1.jpg

GLAUCOMA

2012-04-01T01:29:00.001+05:00

Glaucoma is the clinical condition in which there is adequate increase in intra-ocular pressure. It is one of the leading causes of blindness all over the world.

Anatomy of the eye:

To understand the etiology of glaucoma, one should be well familiar with the anatomy of the eye ball. As shown in fig.1, the eye ball comprises of three coverings: a) Sclera, b) Choroid, c) Retina. Cornea is the anterior most past of sclera.

fig.1 structure of the eye ball

Iris is the curtain in front of the lens, ligaments of zonule, with aperture (pupil) in the center. It allow only adequate rays of light from the object to form the image on the retina. Its radial and circular muscles determine the intensity of light that is required for adequate illumination on the retina. Behind the lens, there is Vitreous Humor which is transparent lequid medium(shown by oblique blue lines in the fig.1). Another important structure is the cilliary body, located at corneo-scleral junction, which produce a very important fluid secretion, i.e, Aqous Humor. This is the brief review of some of the aspects of eye structure that are related to understand the Glaucoma.

Causes of glaucoma:

Now let us proceed to the etiology and important treatment regimens of Glaucoma. As mentioned above the glaucoma is associated with raised intra-ocular pressure. This pressure being applied may be by the fluid secretion of the cilliary body, the aqous humor in the anterior chamber of the eye ball. Physiologically, Aqous humor is constantly produced by the cilliary body. It flows behind the iris and then come out through the pupil on the front of iris, just behind the cornea.

This fluid has to be drained into the canal of Shelmn. The normal intra-ocular pressure, i.e, 12-20mmHg, is maintained by the balance between the production of the fluid and its drainage.

causes:

When there is excess production or
there may be any obstruction in the drainage of aqous humor, this will lead to the raised I.C pressure that eventually lead to the blindness, if it exists chronically and not treated.

Two types of Glaucoma:

Open angle
Closed angle

1. Open angle glaucoma:

It is the chronic condition in which glaucoma persist over the period of time and needs proper treatment to avoid the fatal consequences. This class of glaucoma has got very much interest in modern pharmacology, because of its responsiveness to the appropriate drug therapy with different classes of pharmacological agents.

How to Treat the glaucoma patient:

Basic theme behind the use of pharmacologic agents is "to reduce the aqous humor production or to facilitate the out-flow of aqous humor."

Five groups of drugs are choice of treatment depending upon the condition of the patient.

Cholinomimetics
alpha-blockers
beta-blockers
prostaglandins F2a
Diuretics.

ANTEROLATERAL SYSTEM

2011-12-19T00:39:00.001+05:00

ASCENDING TRACTS
(Sensory physiology)

Before going in to the details of ANTEROLATERAL group of ascending tracts, we should have a clear concept of ASCENDING TRACTS.... ..........

What the ASCENDING TRACTS are?

The answer to this question is that the spinal cord is basically a downward elongated part of central nervous system. Among many different functions which the spinal cord performs, in order to co-ordinate the different body functions, ONE VERY IMPORTANT FUNCTION is that “it acts as a conduit” for the transfer of information between the higher centers of the CNS, i.e. brain, and different internal and external receptor systems, i.e. PNS.

Other functions include,

It acts as a relay center for many types of sensory information.
It acts as a reflex center for eliciting the local reflexes.
It integrates and performs its role in motor control for some repetitive motions, such as walking. Higher signals only make a correction, when necessary.
Some other autonomic functions. Mainly sympathetic, and also parasympathetic to some extent.

The above mentioned functions along with others are mainly a function of CENTRAL GRAY MATTER of the spinal cord, in the neuronal cell bodies. But the spinal cord’s “conduit” function, which is our main topic of discussion now, is carried out through WHITE MATTER of the spinal cord.

So, the antero lateral pathway (also called anterolateral system) can be defined as,

'' the route of passage of primitive type of sensory information through the spinal cord white matter.''

click on the image to enlarge.

antero-lateral system

Overview of the transfer of sensory information through the antero-lateral system.

Receptor (e.g. pain) → peripheral process of sensory nerve root → cell body of the neuron is in dorsal root ganglion i.e. FIRST ORDER NEURON → central process enter the spinal cord via post root → the central process synapse with 2^nd order neuron in substantia gelatinosa of the spinal cord. → these second order neurons send processes which cross to the opposite side → the same process (very long axon) ascend in the anterolateral white matter of the spinal cord on the contralateral side → in the brain stem, this long axon is part of spinal lemniscus˚ → ventro-anterior and vntroposteromedial nuclei of thalamus (2^nd order neuron synapse with 3^rd order neuron here.) → 3^rd order axons pass through the INTERNAL CAPSULE and then fibers eventually end in the somatosensory cortex of the cerebrum.

˚spinal lemniscus consist of spinotectal tract, anterior spinothalamic tract and lateral spinothalamic tract.

Histology Slides 2nd year

2011-12-12T12:58:00.001+05:00

More than 100 Slides for Histology lab. click

Colon and rectum...jpg

Breasts..lactating phase 23.jpg

ADRENAL~1.JPG

Adrenal8.jpg

Adrenal9.jpg

Appendix.8.jpg

Appendix15.jpg

Appendix..46.jpg

Appendix..5+¦7.jpg

Appendix..84.jpg

Appendix..85.jpg

Appendix..debry present in lumen..intestinal glands less in number.jpg

Appendix..lymphocytes present.debry in lumen.jpg

Breasts..lactating phase 23.jpg

Cervix and vagina.jpg

Colon and rectum...jpg

Colon and rectum..2.jpg

Cornea........jpg

Cornea......jpg

Cornea....jpg

Duod..jpg

Duod.2.jpg

Duod.2..LEAf like villi and brunner's glands.jpg

Duodenum.+¿3+¦.jpg

Duodenum..23.jpg

Duodenum..25.jpg

Ear.americ+ñn.jpg

Ear.american.jpg

Epididymis and testes..65.jpg

Epididymis and testes.jpg

Epididymis.aj...jpg

Fallopian tube and broad ligament..jpg

Fallopian tube..58.jpg

Fallopian tube..mucosal lining thrown into longitudinal folds..it is continuous at upper left part of this pic with broad ligament..jpg

GALLBL~1.JPG

Gall bladder.28.jpg

Ileum+¿..CLUB SHAPED VILLI AND PEYERS PATCHES.jpg

Ileum...8.jpg

Ileum...jpg

Ileum..OUTER.jpg

Ileum2.jpg

Duodenum..23.jpg

Duodenum..25.jpg

Jujenum.ELONGATED VILLI.no peyers patches.no submucosal gland.jpg

Kidney...PCT AND DCT are present..jpg

Kidney.medula is present..collecting ducts seen.jpg

Liver..6pg7.jpg

Liver58.jpg

Lungs..5.jpg

Lungs.98.jpg

Oesophagus..+¦3.jpg

Oesophagus..st.squmamous epithelium in upper part.columnar
in lower part..inner circular outer longitudinal.mixed glands.jpg

Oesophagus..65.jpg

Ovary..5.jpg

Ovary..62.jpg

Pancreas+¿.jpg

Pancreas..jpg

Pancreas..outer.jpg

Pancreas.adipocytes are seen.jpg

Pancreas.in the center interlobular duct is present.red colored islets
of langerhans are present..in addition.adipocytes are also seen.jpg

Pancreas.jpg

Pancreas.pale colored islets of langerhans present.jpg

Pancreas2.jpg

Pancreas32.jpg

Parotid gland+¦8.jpg

Parotid gland92.jpg

Parotid gland..8.jpg

Pituitary..2.jpg

Pituitary..anterior pituitary.darkly staining chromophil cells and
lightly staining chromphobe cells are present...jpg

Pituitary..hering bodies are seen as light redded spots in the posterior pituitary..jpg

Prostate...6+¼.jpg

Prostate..6.jpg

Prostate..sadaken.jpg

Seminal vesicle...64.jpg

Seminal vesicle.89.jpg

Stomach 50.jpg

Stomach...jpg

Stomach..3.jpg

Stomach..40.jpg

Sublingual gland...jpg

Submandibular gland..3+¦.jpg

Submandibular..95.jpg

Thyroid gland..3.jpg

Tongue..23.jpg

Tongue..34.jpg

Tongue..38.jpg

Tongue.fungiform papillae.jpg

Trachea...3+¦.jpg

Trachea...jpg

Trachea..OA.jpg

Trachea..hyaline cartilage is seen as a c shaped cartilage...jpg

Trachea..hyaline cartilage...jpg

Trachea..k+¦.jpg

Ureter...jpg

Urinary bladder 50.jpg

Urinary bladder..84.jpg

Uterus6k.jpg

Uterus..BLUe overall.jpg

Uterus...6.jpg

Vas deferens..outer and inner longitudinal middle circular layers are
present..epithelium is pseudostratified columnar epithelium.jpg

Vas defferens...851.jpg

Histology Slides

2011-12-12T12:27:00.001+05:00

More than 60 identification slides. click here.

Identification of tissue slides in the histology labs.

Agonists and Antagonist Drugs.

2011-12-07T17:59:00.001+05:00

animation

Histology Diagrams for M.B;B.S students

2011-12-05T05:20:00.000+05:00

Download All Diagrams click here!

Dorsal Column-Medial Lemniscal System

2010-12-13T19:32:00.000+05:00

The neuronal pathway which carry,

sense of vibration,

highly localized touch sensations,

touch sensations which require fine gradations of intensity,

position sense

through central nervous system is called, Dorsal Column-Medial Lemniscal System

It includes one of the ascending tracts,

dorsal column, present in the white matter of the spinal cord and

medial lemnisci in the brain through the medulla, pons, mid-brain and to the thalamus. where 3rd order neurons are present.

fig.1.1

Route:

Highly localized sensation is well developed in the fingers of human and allows us to feel fine textures and determine what an unknown object in our hands is without looking at it (stereognosis).

First Order Neuron:
Present in the dorsal root ganglion,

peripheral process (as dendrite) from receptor - dorsal root ganglion
central process (as axon) from dorsal root ganglion - gracile nucleus & cuneate nucleus in the medulla.
pseudo-unipolar neuron.

it has long axon which, unlike the antero-lateral system, don't cross the mid-line in the spinal cord

This fine sensation is detected by Meirssner`s corpuscles that lie in the dermis of the skin close to the epidermis. When these structures are stimulated by slight pressure, an action potential is started. Alternatively, proprioceptive muscle spindles and other skin surface touch receptors such as merkel cells, Ruffini endings, Pacinian corpuscles, and hair follicle receptors (Peritrichial endings) may involve the first neuron in this ascending pathway of the spinal cord.

The action potential travels up an axon (the cell body of the neuron will be in a dorsal root ganglion). (The neurons are classified as pseudo-unipolar, so they are regarded as having just one long process, which includes both a peripheral branch dendrite and central branch axon.) So the sensation travels from the skin, along the axon, past the neuronal cell body, and into the dorsal column of the spinal cord.

The axons continue inside the spinal cord, running up the posterior (dorsal) white column as,

fasciculus gracilis formed by axons from lower part of body, medially present.
fasciculus cuneatus. axons from lower part of body above T6, lateral to mentioned above.

At the medulla oblongata, these axons synapse with neurons in the gracile nucleus and cuneate nucleus.

Second Order Neuron:
Present in the gracile nucleus & cuneate nucleus,

cross the mid-line in medulla as internal arcuate fibers and after crossing, it becomes medial lemniscus.
they present sensory decussation in the mudulla.
The medial lemniscus rotates 90 degrees at the pons.

Here, fibers from lower body lie lateral to those from upper.
At the medulla, the medial lemniscus is orientated perpendicular to the way the fibres travelled in the posterior columns. For example, in the columns, lower limb is medial, upper limb is more lateral. At the medial leminiscus, axons from the leg are more ventral, arm fibres more dorsal. Fibres from the trigeminal nerve (supplying the head) come in dorsal to the arm fibres, and travel up the lemniscus too.

The secondary axons from neurons giving sensation to the head, stay at around the same place, while the leg axons move outwards.

The axons travel up the rest of the brainstem, and synapse at the thalamus (at the ventral posterolateral nucleus for sensation from the neck, trunk, and extremities, and at the ventral posteromedial nucleus for sensation from the head).

Third Order Neuron:

Neurons beginning in the thalamus travel up the posterior limb of the internal capsule, and again head and leg swap relative positions. The axons synapse in the primary sensory cortex, with and upper body more lateral while lower body sensation most medial (e.g., the paracentral lobule).
NOTE: To make your concept more clear, listen to the Lectures by dr Najeeb, the greatest teacher, ever.

Dr Najeeb's Lecture on ascending tracts click here.