In this post different types of standard setting methods have been described. Among the different types, fixed percentage method, Angoff's method (Angoffing) and Hofstee have been described with their advantages and disadvantages.Commonly used standard setting methods for objective structured clinical examination (OSCE) have also also been described.
PRINCIPLES OF TERATOLOGY AND CRITICAL STAGES OF DEVELOPMENT
This note defines a teratogen and explains the principles governing the capacity of a teratogen to produce teratogenic effect with emphasis on the effect of a teratogen on different developmental stages.
HISTOLOGICAL FEATURES OF SPLEEN
General
Structure of spleen
The
spleen is the largest accumulation of lymphoid tissue in the body. The spleen
is surrounded by a capsule of dense connective tissue from which emerge trabeculae,
which divide the parenchyma, or splenic pulp, into incomplete
compartments. Large trabeculae originate at the hilum, on the medial surface of
the spleen; these trabeculae carry nerves, arteries and veins.
In
humans, the connective tissue of the capsule and trabeculae contains only a few
smooth muscle cells, contrary to what occurs in several animals (eg, horses,
dogs, and cats).
GROSS ANATOMY OF SPLEEN
Shape of Spleen
The spleen is an ovoid, usually purplish, pulpy, soft, vascular (sinusoidal)
mass about the size and shape of one's fist. The spleen is 1 inch thick, 3
inches wide, 5 inches long, and weighs 7 ounces.
HISTOLOGICAL FEATURES OF TONSIL
Tonsils
Tonsils belong to the mucosa associated lymphoid tissue (MALT),
but because they are incompletely encapsulated, they are considered organs and
will be studied apart from the MALT. The tonsils constitute a lymphoid tissue
that lies beneath, and in contact with, the epithelium of the initial portion
of the digestive tract. Depending on their location, tonsils in the mouth and
pharynx are called palatine, pharyngeal, or lingual.
HISTOLOGICAL FEATURES OF LYMPH NODE
Lymph
Nodes
Lymph
nodes are distributed throughout the body along the course of the lymphatic
vessels. The nodes are found in the axilla and the groin, along the great
vessels of the neck, and in large numbers in the thorax and abdomen, especially
in mesenteries. Lymph nodes constitute a series of in-line filters that are
important in the body's defense against microorganisms and the spread of tumor cells.
All this lymph, derived from tissue fluid, is filtered by at least one node
before returning to the circulation.
Gross
Features of Lymph Nodes
Lymph nodes are elongated or kidney-shaped organs that
have a convex surface that is the entrance site of lymphatic vessels and a
concave depression, the hilum, through which arteries and nerves enter
and veins and lymphatic vessels leave the organ (Figure- 1). A connective
tissue capsule surrounds the lymph node, sending trabeculae into its
interior.LYMPHOID TISSUE: A BRIEF OUTLINE
The body has a system of cells—the
immune system—has the ability to neutralize or inactivate foreign molecules
(such as soluble molecules as well as molecules present in viruses, bacteria,
and parasites) and to destroy microorganisms or other cells (such as
virus-infected cells, cells of transplanted organs, and cancer cells).
1. They are distributed throughout the body in
the blood, lymph, and epithelial and connective tissues;
2. They are arranged in small spherical nodules
called lymphoid nodules found in connective tissues and inside several
organs and
3. They are organized as differently sized
organs called lymphoid organs— like the lymph nodes, the spleen, the
thymus, and the bone marrow.
a. Spleen and thymus are called primary or
central lymphoid organs.
b. Lymph nodes, spleen and other lymphoid
tissues line tonsil are called secondary or peripheral lymphoid organs.
MUSCLES OF RESPIRATION
Respiration involves Inspiration and Expiration
which are accompanied by the alternate increase and decrease of the volume of
thoracic cavity.
Inspiration is an active process and is achieved by increase
in all diameters of thoracic cavity. (Thoracic cavity has three diameters –
vertical, transverse and anteroposterior.)
The muscles involved in inspiration are:
Diaphragm:
Diaphragm is the primary muscle of inspiration.It
increases all the three diameters of thorax.
GROSS ANATOMY AND HISTOLOGICAL FEATURES OF THYROID GLAND
The thyroid is a highly vascular
ductless gland found deep in the neck region and overlapped by the anterior
neck muscles.
Location of the thyroid gland:
It situated in front and at the
sides of trachea opposite 5th, 6th, 7th cervical and 1st thoracic vertebrae in the neck
region.
Intrinsic or Deep or Paraspinal Muslces of Back: Brief Outline
What are Paraspinal Muscles or Deep Muscles or Intrinsic Muscles of back?
These
are deep or intrinsic back muscles. These muscles form a prominent mass on each
side of the spinal column extending from base of the skull to the sacrum. These
muscles consists of many separate, overlapping muscles of different lengths,
attached to the spinous or transverse processes of different vertebrae.
Structure and Function of Skin
Structure of Skin
Layers
of the skin (from superficial to deep) are:
Epidermis
– it is made up of stratified squamous epithelium keratinized
Dermis
– it is made up of connective tissue.
Cranial Dura Mater and Dural Venous Sinuses
Objectives:
Describe the features (and
reflections/foldings) of cranial dura mater.
Describe the intracranial dural venous
sinuses.
The brain is covered from outside
inwards by three meningeal layers namely
i)
Dura mater
ii) Arachnoid
mater and
iii) Pia
mater.
Dura
Mater:
It is tough and consists of
outer
endosteal/periosteal layer which serves as inner periosteum
(covering inside of the bones that form the calvaria of skull) and
inner
meningeal layer which is a strong fibrous membrane that is continuous at
the foramen magnum with the spinal dura mater covering the spinal cord.
Muscles of the Eye-lid: Actions and Innervations
Objective
Describe the muscles of eye lid, their actions and innervations.
Muscles of eyelid: Their Actions and Innervations
The
muscles of the eyelids are:
Levatorpalpebræsuperioris (LPS)
Orbicularis oculi
Corrugator
Extra-ocular Muscles of Eye: their attachment, actions and nerve supply
Objectives:
Describe the attachment of extra-ocular muscles.
Describe the action and nerve supply of extra-ocular muscles.
Extra-ocular muscles of eye
The muscle acting on the eye ball to produce various
movements of eye are called extr-aocular muscles which consists of
Four recti
|
Two oblique muscles
|
Superior rectus
|
Superior oblique
|
Inferior rectus
|
Inferior oblique
|
Medial rectus
|
|
Lateral rectus
|
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