Bone Cells + Structure Osteons + Blood Connective Tissue

Osteogenic Cells (what they are)

mesenchymal stem cells that start to develop, start to lay down collagen, become trapped and become osteoblasts

Osteoblasts (functions(3))

bone-forming cells. Lay down more collagen, mineralization process starts

Osteocytes (what they are + 2 functions and 1 feature)

mature bone cells derived from osteoblasts trapped in the ECM

Function: mantain bone tissue and are involved in exchange of nutrients and waste

Feature - have gap junction communicate with other osteocytes

Osteoclasts (what they are + function)

large multinucleated cells formed from fusion of blood monocytes

Function: break down bone

Now moving onto structure osteons

Lamellae (features + purpose)

concentric rings of mineral salts for hardness(e.g calcium phosphate and CaOH which form hydroxyapatite) and collagen (tensile strength)

Lacunae (location + feature)

small spaces between lamellae that contain mature bone cells (osteocytes)

Canaliculi

minute canals (containing EC fluid and minute osteocytic processes) that radiate from lacunae and provide routes for O2, nutrients and waste

Central (Haversian) canal (location(3)

blood, lymph, nerves

When bone fractures (4 steps)

1. osteoclasts reabsorb dead bone

2. Chondroblasts lay down hyaline cartilage callus

3. Osteoblasts lay down new base

4. Osteoclasts remodel new bone

Liquid CT: Blood - Structure (2)

Consists of blood plasma (a liquid ECM) and formed elements

Erythrocytes - Function

Function: transport O2 and CO2

Leukocytes - Function and types

combat disease

Two types: granular and agranular

Neutrophils and monocytes (macrophages) - (feature + function)

Type: Granular

Feature: phagocytic

Function: engulf bacteria

Basophils (mobile) and mast cells (immature circulate, mature are fixed in tissues) - function

Type: granular

release substances e.g histamine that intensify inflammatory reaction

Eosinophils - functions

Type: granular

effective against certain parasitic worms and in acute allergic response

Lymphocytes - function

Type: agranular

involved in immune response

Platelets - where from and function

from megakaryocytes in red marrow

Function: clot to prevent bleeding