6. Connective tissue. Histogenesis. General characteristics. Classification.

Connective tissue is a combination of __________ and has lots of __________ substance.

cells; intercellular material that provides support and structure.

Connective tissue derives from __________ and has productive, protective and __________ functions.

mesenchyme; trophic functions that provide nourishment and maintenance to various tissues.

Fibroblasts, osteoblasts and chondroblasts are examples of __________ cells.

productive cells that are responsible for the synthesis of fibers and extracellular matrix.

Macrophages, mast cells and plasma cells are __________ cells.

protective cells that play critical roles in immune response and defense against pathogens.

Pigment cells contain __________ and can be found in various tissues such as the skin and eye.

melanin; a pigment that provides coloration and protection against UV radiation.

Adipose tissue is derived from __________.

mesenchyme; a type of connective tissue specialized in storing energy as fat.

There are two types of adipose tissue: white adipose tissue and __________ adipose tissue.

brown; which is specialized for energy expenditure and thermogenesis.

White adipose tissues contain __________ adipocytes and a single large __________ droplet.

unilocular; lipid droplet that stores energy efficiently.

Mature connective tissue is split into two categories: with fibrous intercellular substance and with __________ intercellular substance.

solid; which refers to a more rigid structure, such as bone.

Connective tissue is found as __________ between the structures in the organism.

packing material that fills spaces and provides support to organs and tissues.

Collagen fibres are the __________ type of fibres and are formed by __________.

most numerous; fibroblasts which produce collagen as a primary structural protein.

Elastic fibres are arranged in bundles to form a __________ network and are found in __________.

three-dimensional; ligaments and other structures that require elasticity and resilience.

Reticular fibres are made of __________ collagen and are found in lymphoid organs, lymph nodes, bone marrow, and spleen.

type III; which form a supportive lattice for cells in these organs.

Hyaline cartilage is the __________ common type of cartilage and consists of 3-5 isogenous groups with lots of __________.

most; chondrocytes, which are mature cartilage cells that maintain the cartilage matrix.

Fibrocartilage has thick bundles of __________ fibres and is found in intervertebral discs, joint capsules, and the cruciate ligament.

collagen; which provide tensile strength and support for high-stress areas.

Bone is a connective tissue because its matrix is __________ by calcium phosphate.

mineralized; which gives bone its hardness and strength.

The __________ is the main structural unit of bones consisting of bone lamella, osteocytes, and osteoclasts.

osteon; which is the fundamental functional unit that supports the structure and function of bone.

Osteoblasts elaborate bone matrix and have a __________-stained cytoplasm.

basophilic; indicating extensive rough endoplasmic reticulum involved in protein synthesis.

Osteocytes maintain bone tissue and are involved in __________, growth, and repair of the bone.

remodeling; which is the process of renewing and reshaping bone tissue.

Osteoclasts are multi-nucleated and involved in the __________ of the bone matrix.

breakdown; which is essential for bone remodeling and maintenance by resorbing old bone.

what are the productive cells?

fibroblasts, osteoblasts, chondroblasts

trophic cells

adipocytes

pigmentous cells

protective cells

macrophage

mast cell

plasma cell

fibroblast description

• originates from the mesenchyme

• spindle-shaped

• large nucleus

• cytoplasm is basophilic-stained

• has well developed golgi apparatus and rough ER

macrophage description

• from monocytes

• many lysosomes, golgi apparatus, mitochondria, SER, RER

• involved in phagocytosis

plasma cell description

• originates from b-lymphocytes

• produce antibodies

• many rough ER and golgi apparatus like fibrocytes

• nuclei is eccentrically placed with heterochromatin

mast cells description

• arise from basophil granulocytes

• play a role in allergic reaction

• have serotonin, histamine and heparin

pigment cell description

• contain melanin

• can be found in skin, iris, meninges of brain, choroid of eye

• melanin made my melanocytes in the melanophores

adipose tissue description

• derived from mesenchyme

• two types white adipose and brown adipose

• white is unilocular and have a single lipid droplet

• brown is multilocular with several lipid droplets and used for thermoregulation

what are the types of connective tissue?

embryonic and mature

embryonic CT

mucous and mesenchyme

mature CT

divided based on intercellular substance

fibrous intercellular substance - collagenous CT, elastic CT, reticular CT, dense CT, loose CT, pigment CT, adipose CT

solid intercellular substance - dentin CT, bone CT, cartilage CT

what are the 3 types of fibers in CT?

• collagen

• reticular

• elastic

collagen fibres description

• most numerous

• arranged in bundles of straight and branched fibrils

• have collagen

• is present in ALL types of CT

• formed by fibroblasts

elastic fibres description

• fewer

• arranged in bundles to form 3D network

• found in ligaments

reticular fibres description

• made of type III collagen,

• finer than collagen, uneven in thickness also form a network

• found in lymphoid organs, lymph nodes, bone marrow, spleen

• produced by fibroblast

• characterised by optical homogenity, metachromasia, hydrophilia

hyalin cartilage

hyalin - most abundant, found in ribs, articular cartilage and respiratory system, consists of 3-5 isogenous groups, many chondrocytes, has metachromatic-stained intercellular matrix due to proteoglycans

fibrocartilage

has thick bundles of collagen fibres and many rows of isogenous groups

strongest type of cartilage and found in the intervertebral discs, joint capsule and the cruciate ligament of the knee

elastic cartilage

• isogenous groups 1-2 chondrocytes and has a perichondrium

• found in the external ear, epiglottis and larynx

how is bone CT?

• matrix is mineralised by calcium phosphate

• osteon is the main structural unit of the bones consisting of bone lamella, osteoclasts and osteocytes

• there is spongy and compact bone

osteoblast recap

• elaborate bone matrix

• highly active young cells

• have basophilic-stained cytoplasm

• many mitochondria and endoplasmic reticulum

osteocyte recap

• mature osteoblasts less active

• maintain bone matrix

• involved in remodelling, growth and repair

osteoclast recap

• involved in bone matrix degradation and bone resorption

• act as macrophages have acid phosphatase and lysosomes

• multinucleate

• derived from the fusion of monocytes like macrophage

• microvilli present on the surface