Cells and Tissues Flashcards
Which germ layer do mesenchymal tissue arise from?
Mesoderm
What tissues are included in the term mesenchymal tissues?
Blood, Lymph, Fat, Cartilage, Muscle, Bone
What are the 2 main components of connective tissue?
Cells and ECM
What makes up the extracellular matrix?
Ground substance containing glycosaminoglycans (structural carbohydrates), glycoproteins and proteins, through this runs collagen fibres (Strength) and elastin fibres (elasticity) also contains percolating tissue fluid
What cells are found within the ECM in connective tissue>
1) Fibroblasts (active during healing, make collagen, elastin and glycosaminoglycans)
2) Adipocytes (Store fat)
3) Immune cells: Macrophages, mast cells (produce vasoactive substances) and Plasma cells
What are mononuclear leucocytes and name one?
No lobed nuclei, include lymphocytes (B and T cells)
What are granulocytes and name some?
Have lobed nuclei and granules in cytoplasm, include neutrophils, eosinophils, basophils
Other than leucocytes what are the other components of blood?
Erythrocytes, platelets, Proteins (including immunoglobulins, albumin and fribrinogen), hormones, nutrients, gases and plasma
What might occur if lymph nodes are removed?
Lymphodema because lymph cannot be removed from tissues
What are the cells found in the ECM (called osteoid) of bone?
1) Osteoblasts: make osteoid
2) Osteocytes: found in mature bone, osteoblasts which have become trapped once bone calcifies and now maintain bone
3) Osteoclasts
What are the cells found in the ECM (called osteoid) of bone?
1) Osteoblasts: make osteoid (collagen fibres are found within it)
2) Osteocytes: found in mature bone, osteoblasts which have become trapped once bone calcifies and now maintain bone
3) Osteoclasts: resorb bone (break it down) in response to stress on bone, growth, calcium status
How is bone formed?
First bone formed by osteoblasts is woven and immature, collagen fibres are random, as immature bone is calcified (initiated by osteoblasts) bone becomes harder and woven bone is replaced by lamellae bone where collagen fibres are in parallel layers
What is compact and cancellous bone?
Compact outer bone, shafts of long bones,
Cancellous (spongy) inner bone, found at end of long bones
What is periosteum and endosteum?
Periosteum = dense fibrous layer on outside of bone Endiosteum = tissue lining inner bone
What are the functions of cartilage?
1) form a supporting framework for organs
2) form articulating surfaces for bone
3) form a template for development and growth of long bones
What are the constituents of cartilage?
1) ECM made up of ground substance and collagen fibres
2) Cells including chondroblasts (make ECM and collagen fibres) and chondrocytes (mature chondroblasts trapped in collagen)
What are the 3 types of cartilage and where are they found?
1) Hyaline: glossy, nose trachea
2) Fibrocartilage: intervertebral discs, pubic symphysis
3) Elastic cartilage: found in ears
What is Marfan’s syndrome?
Defect in fibrillin protein, joint laxity, cataracts, valvular heart disease, aortic wall weak
What is scurvy?
connective tissue disorder that results from ascorbic acid deficiency
What role does histology have in medicine?
Diagnosis of cancer and many non malignant diseases, identifying prognostic features, therapeutic information can be gained from histology and special stains can identify the presence of drug targets within tissues
In histology what is the purpose of fixation?
Prevent degradation of tissues either by bacteria, autolytic enzymes or trauma, heat or chemicals may be used, achieved by forming covalent bonds within proteins or venturing proteins
What is formalin?
Most common Fixative in histology, forms covalent bonds between proteins
In histology what are the pros and cons of formalin?
Reliable, penetrates tissue well but its toxic/an irritant and not good for cytoplasmic structures but good for overall morphology
In histology what are the pros and cons of the Fixative glutaraldehyde?
Good for cytoplasmic structures and used for electron microscopy but doesn’t penetrate tissue well so only small pieces can be fixed