Macrophages also known as clasmatocytes are phagocytic cells. These are modified monocytes.
Fibroblast cells produces white and yellow fibers such cells are largest and main cells of an areolar tissue. They secrete matrix also.
These cells are modified B-lymphocytes.
They secrete antibodies.
Fat cells (adipocytes)
These are fat staring cells.
They have a large fat droplet called blob in the cytoplasm or may have many fat droplets.
These are pigmented cells with melanin pigment.
These are undifferentiated cells.
Made up of elastin protein
Made up of protein
Made up of Reticulin protein
Straight branched and singly arranged
Way, Unbranched and arranged in bundles.
Highly branched.Forming network.
It is modified areolar tissue.
It has closely packed cell called adipocytes containing fat globules.
The intercellular matrix is negligible.
These adipocytes are of further of 2 types ,named monolocular (white fat cell) and multilocular (Brown fat cells).
White fat cell has a single large fat globule (bolb) and less cytoplassm. Brown fat cell has many fat globules and more cytoplasm.
Brown fat cell produces 20 times more energy than white fat cell.
Dense Connective Tissue Matrix has compactly I densely arranged fibres and connective tissue cell. These are of following types;
White Fibrous Connective Tissue
Only collagen fibres are present in the matrix and cells are mainly fibroblasts and mast cells.
Cells and fibres are riss-crossed arranged. Example; Periostium, Perichondrium, Epimysium, Dura mater
Bundles of collagen fibres are distributed in regular patter in matrix.
Fibroblasts (tendocytes) are arranged in series.
Mast cells are scattered. Examples; Tendon that connects muscles to bones.
Yellow Fibrous Connective Tissues
Mostly yellow elastin fibres are present in the matrix and cells are mainl fibroblasts.
Irregular distribution of yellow elastin fibres in matrix. Examples; wall of alveoli, wall of small pronchioles, vocal cords.
Yellow elastin fibres form dense network in matrix.
Example; ligaments that connects bones to bones.
Reticular Connective Tissue
Matrix is lymph like.
Matrix has dense network of reticulin fibres around star like reticular cells.
A few mascrophages, lymphocytes and adipocytes are also present.
Present in Lymphnodes, Thymus, Tonsil, Spleen, Bone marrow
These are associated with phogocytosis and provide strength and support to soft organs.
Skeletal Connective Tissue This tissue includes bone and cartilages.
Bone Bone-outer covering contains white fibrous connective tissues called Periosteum. Bone- forming cells are called Osteoblasts. Proteins of bone is Ossein.
Matrix is hard and is composed of ossein protein
It forms thin plates called lamellae
Matrix has phosphates and driumcarbonates of calcium and magnesium. Ca3(Po4)2 is abundant (80%).
Matrix has longitudinal canals called Haversian canals and transverse canals called Volkmann's Canals.
Haversian canal has blood vessels, Lumph vessels and nerve fibres.
Haversian canals are interconnected by volkmann's canals.
Lamellae have small cavities called lacunae which gives fine branching tubules called canaliculi.
Lacuna has bone forming cells called osteocytes with filopodia.
Endosteum is present outer to the bone marrow cavity.
Marrow cavity is filled with bone marrow (soft connective tissue).
It is of two types; Red bone marrow and Yellow bone marrow.
Red bone marrow helps in blood cell formation.
Yellow bone marrow stores fats.
Bones form endoskeleton.
Cartilages Outer covering in which white fibrous connective tissue of cartilage is perichondrium. Cartilage forming cells are chondroblasts. Its protein is Chondrin. Chondrocytes are scattered in matrix.
Matrix is rubber like and translucent.
Each lacuna has 2-4 chondrocytes (Cell nest).
Depending upon types of fibres present, cartilage is classified as:
Matrix has no fibres or a few collagen fibres.
Matrix is glassy and bluish.
It is found is nasal septum, rings of trachea, larynx, ends of long bones(articular cartilage)
Most of the embryonic skeleton is made up of Hyaline cartilage.
Matrix has networks of elastic fibers.
Matrix is yellowish.
Highly elestic cartilage.
It is found in tip of nose, ear pinnae, epiglottis, wall of eustachian tubes.
White fibrous cartilage
matrix has bundles of collagen fibers
It forms public symphysis, intervertebral dises, adhesive capsules.
It is formed by calcification of Hyaline cartilage.
Less elastic and more rigid.
It is found in head of femur and humerous, suprascapula, xiphisternum.
Fluid Connective Tissue or Vascular tissue It include blood and lymph.
It is made up of plasma and blood cells (formed elements).
Plasma is transparent, yellowish fluid form 55 % of blood.
It has 90 % water, 8 % plasma proteins and 2 % other dissolved substances.
Important plasma proteins are albumin, globulins, fibrinogen, antibodies, prothrombin
Blood cells forms 45% of blood.
Blood cells are RBCs, WBCs and Platelets.
RBCs (erythrocytes) are circular, biconcave and denucleated.
Total RBC Count is 4.5-5 million/mm3.
It is made up of haemoglobin respiratory pigment also provide red colour to blood.
Formation of RBC is called erythropoiesis.
It occurs in red bone marrow.
It life span is 120 days.
Destruction of RBC is called erythrolysis that occurs in spleen, bone marrow and liver.
WBCs (leucocytes) are colourless, nucleated and complete cells.
Total leucocyte count is 4000-11000/mm3 of blood.
They are formed in bone marrow, spleen, thymus and lymph nodes and the process is called Leukopoiesis.
Life span is 10-13 days.
WBCs are of two types: granulocytes and agranulocytes
Granulocytes Lobed nucleus and granules in cytoplasm;
's'- shaped nucleus
absorb acdic stains
absorb basic stains.
absorb both acidic as well as basic stains
secrete histamine and protect the body against allergy and parastic infection
Secrete heparin and histamine
Agranulocytes Simple nucleus and clear cytoplesm
Largest cells with eccentrically placed kidney-shaped nucleus.
Rounded cells with large Spherical nucleus.
Motile and Phagocytic
Blood platelets(thrombocytes) are pragments of gaint megakaryocytes of bone marrow.
Total blood platelet count is 3 lacs /mm3
Life span is about 7 days.
Blood platelets contain thromboplastin that helps in clotting of blood.
Colourless fluid formed by filtration of blood.
Contains plasma, lymphocytes, dissolved O2 and CO2, insoluble protains, nutrients etc.
Provide immunity to body and helps in exchange of materials between blood and tissues.
Nervous Tissue Ectodermal in origin. Nervous tissue is composed of neurons (nerve cells) and supporting and protective cells called neuroglial cells, nerves, ependymal cells and neurosecretory cells.
Neurons These are 3 types-
Unipolar or Pseudounipolar neurons in such neurons ,single process arises from the body of cell and bifuracetes ,to form the Axon and dendrites. Examples are dorsal root ganglion of spinal cords.
Bipolar neurons they have two poles, one dendrite and one axon arising from the cell body.Example neurons arising from the retina and internal ear.
Such neurons have one or more than one dendrites.
99% of the dendrites are multipolar types.
The structure of Neurons
It consists of three parts Dendrites, cyton and axon.
System is irregularly spherical or oval shaped and certain abundant neuroplasm.
Cyton contains large nucleus ribosomes, Nissl granules, Golgibodies, Mitochondria and Neuro fibrils.
The centrosome is absent in cyton and can’t be the divide.
Dendrites are shorter and branched processes arising from system.
They carry impulse towards towards system.
Axon is long process with highly branched terminal arborization with terminal battery.
Axon has plasma membrane called axolemma and cytoplasm called axoplasm.
Axon may be myelinated are non myelinated. It is externally covered by neurilemma made up of flat schwann’s cells.
Myelinated axon has gaps called node of Ranviers.
Structure of Nerve
Bundles of nerve fibres is called Nerve.
The outer covering or the connective tissue covering the nerve is called epineurium.
These are several bundles of neurons embedded in epineurium and such bundles are known to be fascicula.
Each nerve fasciculus has a connective tissue called perineurium.
Single neurons are also surrounded by connecting tissue covering called Endoneurium.
Types of nerves On the basis of their function, the nerve is 3 types
Sensory These impulses is carried from receptors (skin, retina etc) to the CNS. EG optic nerve.
Motor These are carried by an impulse from CNS to effector organs. Eg trochlear nerve.
Mixed In such nerves, some fibres carry impulses towards CNS and other away from the Brain of CNS.
Neuroglia cells These are mesodermal in origin. These are supporting cells essential for normal functioning of nervous tissue. These are of following types
Microglia Phagocytes of brain
Astrocytes Control microenvironment of neuron.
Oligodendrocytes Form myelin in Neurons.
Ependymal cells Lines the cavities of brain and spinal cord.
Neurosecretory cells Neurons of Hypothalamus that secret neurotransmitters which stimulates anterior lobe of pituitary to secret trophic hormones.