Ordinary connective tissue (connective tissue proper)

Ordinary connective tissue (connective tissue proper)

This types of connective tissue bears no special character or features.They only connect two types of tissue together. For example transitional epithelium of urinary bladder connected with smooth muscles layer by connective tissue known as lamina propria. 

Classification of ordinary connective tissue:

1. Loose connective tissue : why it is known as loose because it contain loosely arranged connective tissue fibres 

2. Dense connective tissue : why dense ? because it contain densely arranged connective tissue fibres. According to manner of arrangement of connective tissue fibres it is again two types:

Dense irregular connective tissue: dense connective tissue fibres arranged irregularly 

Dense regular connective tissue : dense connective tissue fibres arranged regularly   

Loose connective tissue contain large number of connective tissue cells but less and loosely arranged connective tissue fibres. Example: lamina propria of mucosa of intestine (it handle stress and allow distension)  

Dense irregular connective tissue : contain less connective tissue cells but densely and irregularly arranged connective tissue fibres: Example : dermis of skin ( irregularly arranged connective tissue fibres bear more stress from any direction ) 

Dense regular connective tissue contain less connective tissue cells but densely and regularly arranged connective tissue fibres  : example: tendon (it bear more stress but from particular direction ) 

Ganglia and nucleus : similarity and difference

Nucleus : 

collection of nerve cells bodies within the central nervous system.

SN:

1. Big collection of nerve cells body within the central nervous system is known as grey matter. 
2. Small collection of nerve cells body within the central nervous system is known as nucleus. 
3. Some time part of grey matter is also known as nucleus. 
4. Some time the axons of nucleus leaves the central nervous system as peripheral nerve

Ganglia : 

Collection of nerve cells bodies outside the central nervous system is known as ganglia.

SN:

Nerve cells bodies of ganglia some time synapses with axon of other neuron 

Some time axon of other neuron only passage through the ganglia 

Some time ganglia connect with each other so axon of one ganglia passage above ganglia or below ganglia 

Some ganglia near to central nervous system but some are nearer to target organ 

Similarity between nucleus and ganglia : both are collection of nerve cells bodies 

Difference between nucleus and ganglia: nucleus lies within CNS and ganglia lies within PNS  

Nucleus: at a glance

Nucleus 

Parts of nucleus

•      Nuclear membrane

•      Nucleolus

•      Chromatin &  nucleoplasm

Nuclear membrane

•      It is a double layer membrane. The outer layer of membrane attached with ribosomes and continuous with rER.

•      Pores present 

Nucleolus:  

1. It is a structure found in the nucleus of cells.

2. It is formed by proteins and nucleic acids. 

3. It is occupies about 25% of the volume of the cell nucleus.

Function:

 It transcribes ribosomal RNA (rRNA)

The synthesis of RNA is regulated by five different chromosomes (13, 14, 15, 21, and 22). 

 Malfunction of nucleoli : 

mutation causes malfunction  of nucleus and it is related to following disease like Weine syndrome, Treacher Collins Syndrome and dyskeratosis.

      Chromatin / Chromatin granule- 

        The readily stainable substance of a non dividing cell nucleus consisting of DNA and RNA and various     

            proteins; during mitotic division it condenses into chromosomes

•      They are two types: 

Heterochromatic

Densely packed portion of chromatin which is genetically inactive.

Bluish in colour. 

Euchromatic
 uncoiled portion of chromatin which is genetically active.
 Lightly stain 

What is chromosome?

•      it is  a  threadlike structures, which visible during cell division and is composed by

•      DNA,

•      Small RNA,

•       histone and non-histone protein. (consisting of genes that are responsible for the transmission of hereditary characteristics)

Types of chromosome:

 Autosomes chromosome:

•      The genes which regulate body character.

•      They are 22 pairs

 Sex chromosome: 

•      The genes which regulate sex character.

•      They are 1 pair

•      In male one X and one Y .

                  XY

•      In female two X.  

                        XX

Chromosomes number in human body

•      46

•      /23 pairs

•       22 pairs autosomes + 1pair sex chromosome

Diploid: A cell or an organism consisting of two sets of chromosomes:

Usually, one set from the mother and another set from the father.

In a diploid state, the haploid number is doubled, thus,

This condition is also known as 2n.

Haploid: The number of chromosomes in a gamete of an organism, symbolized by n. 

Parts of a chromosome

Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.”

 The short arm of the chromosome is labeled the “p arm.”

The long arm of the chromosome is labeled the “q arm.

Chromatid - one of two identical strands into which a chromosome splits during mitosis

Short question on Superior extremity

1. How many compartment present in arm?

Ans : Anterior compartment : which is innervated by musculocutaneous nerve
       Posterior compartment : which is innervated by radial nerve

2. How many compartment present in forearm?

Ans: Anterior compartment : which is innervated by mainly by median nerve and partly by ulnar  nerve
       Posterior compartment : which is innervated by radial nerve

3. Which nerve of upper limb innervated two compartment of upper limb?

Ans : Radial nerve which is innervated both posterior compartment of arm and forearm

4. Musculocutaneous nerve, what is the meaning of musculocutaneous ?

Ans: This nerve pierce the corabobrachialis muscle and end as cutaneous nerve known as lateral cutaneous nerve of forearm.

5. Which nerves innervated muscles of hand ?

Ans: Mainly ulnar nerves supply most of the muscles of hand  and some are supplied by median nerve

6. Which nerve plexus supply upper limb? 

Ans: Brachial plexus

7. What types of plexus is it ?

Ans: somatic plexus

8. How it is formed? 

Ans: it is formed by ventral rami of C 5 to 6 and T 1 spinal nerve

9. What do you mean by pre- fixed and post fix types of brachial plexus 

Ans: pre- fixed brachial plexus : formed by C 4 to 8 

Post fixed: formed by C6 to 8 T1-2

10 What is nerve plexus?

Ans: net of nerves. they are ventral rami of spinal nerves at different label

Thymus : Histological identifying points with easy drawing idea

Thymus : it is a primary lymphatic organ.

Features of Thymus:

1. It is covered by capsule 
2. trabeculae, the extension of capsule divide the organ into lobules 
3. Each lobule has outer cortex and inner medulla 
4. it contain no lymphatic nodule 
5. It contain only T lymphocytes 

Histological features of Thymus
1. each thymic lobule has outer cortex and inner medulla
2 inner medulla contain Hassel's corpuscle
3. outer cortex contain no lymphatic nodule

Lymph node : Histological features with easy drawing idea

Lymph node: 

1. It is the one of the important lymphatic organ. 
2. It is a secondary lymphatic organ 
3. It has one efferent lymph vessel but many afferent lymphatic vessel 
4. Its efferent lymphatic vessel leave through hilum 
5. Its afferent lymphatic vessels enter to this organ at different location 
6. It is covered by capsule
7. It has two part outer cortex and inner medulla 
8. Outer cortex contain lymphatic nodule 

Lymphatic nodule: 

A round shape structure, which is formed by aggregation of lymphocytes

It is darkly stain (deep blue) because lymphocyte contain big nucleus with little cytoplasm

Which lymphatic organ contain lymphatic nodules?

Ans:  

1. Lymph node 
2. Spleen 
3. Tonsil 

GULT: Gut associate lymphatic tissue contain aggregation of lymphocyte mainly in initial and terminal part of alimentary tract 

BULT: Bronchus associate lymphatic tissue contain aggregation of lymphocyte at initial part of respiratory system 

Germinal center: 

A pale stain area within the lymphatic node 

It contains B Lymphocyte 

Why this area pale ? 

It contain immature lymphocyte 

the cytoplasm of immature lymphocyte is bigger the nucleus and the number of cells are less so this area seem to paler than periphery 

 Special feature for identification of histological slide :

1. Subscapsular sinus is present ( unique feature of Lymph node) 
2. It has two parts outer cortex and inner medulla 
3. Outer cortex contain lymphatic nodule 

Organization of peripheral nerve Vs organization of skeletal muscle: easy understanding

Peripheral nerve : it is a collection of nerve bundles surrounded by a connective tissue coat, epineurium . 

Nerve bundle : it is a collection of nerve fibres surrounded by a connective tissue coat, perineurium 

Nerve fibre: it is a process of a neuron (usually axon) surrounded by myeline sheath (schwann cells) and  a connective tissue coat, endoneurium. 

Skeletal muscle: it is a collection of muscle bundles surrounded by a connective tissue coat, epimysium.

Muscle bundle: it is a collection of muscle fibres (muscle cells) surrounded by a connective tissue coat, perimysium.

Muscles fibre: when an individual muscle cells are surrounded by a connective tissue coat, endomysium.