Connective tissue Flashcards
What distinguishes a tissue?
Few cells dispersed in abundance of extracellular material.
Examples of tissues?
-Loose connective tissue attached to epithelial tissue
-Tendons
-Bone
-Blood
Specialised cells in bones?
-Osteoblasts
-Osteoclasts
-Osteocytes
What makes bone different to cartilage?
Calcium phosphate crystals, making bone harder.
How do bones grow?
Osteoblasts deposit new bone on outer and osteoclasts dissolve bony tissue.
Ossification steps?
1) Chondrocytes undergo cell division
2) Older chondrocytes grow larger
Epiphyseal plate grows.
3) Matrix calcifies, trapped chondrocytes die
4) Dead cleared by osteoclasts
5) Osteoblasts deposit new bone
Osteoclasts role
Trapped osteoblasts = Osteocytes
Involved in regulating exchange of calcium between bone and blood.
Controlled by PTH
What hormone promotes bone growth
IGF-1
What do osteoblasts do to fix broken bone?
Move into cavity and secrete osteoid to fill the hole.
What can help osteoporosis?
Exercise - stimulates bones
Tissues of skin?
-Protective epidermis (inner + outer)
-Connective tissue dermis
Epidermis
Epithelial cells
Outer cells flattened and dead as nor blood supply.
Cells held by desmosomes and keratin filaments.
Keratinised layer?
Provides airtight and water proof layer to skin, thickness varies.
Dermis
Tissue layer of elastin and collagen, blood vessels and nerve endings.
Sensory layer.
Controls goosebumps and gland secretion.
Exocrine sweat and sebaceous glands
Sweat - release water to regulate body temp
Sebaceous - release oil on hair and keratin layer.
Hypodermis
Fat cells
What do melanocytes release?
Melanin - skin pigment.
What do keratinocytes release?
Keratin - Nail and hair and protection
What is blood?
Transport Medium within which material is moved long distances.
Specialised blood cells?
Platelets
Erythrocytes
Leukocytes
Suspended in platelets.
What does plasma do?
Maintain bp and proteins control pH
Plasma proteins
Albumins
Globulins
Fibrinogen
Synthesised in liver by lymphocytes.
What is erythrocytes
red blood cells
biconcave
haemoglobin
What are erythropoiesis
Detect oxygen levels in blood.
Leukocytes?
White blood cells
Immune defence
Types of leukocytes
Neutrophils - phagocytosis specialists
Eosinophils - Allergic reaction
Basophils - Histamine
Monocytes - Phagocytes
Lymphocytes - B (antibodies) T (specific target cells)
Platelets?
Fragments
Concentration of actin and myosin
Important for homeostasis
Homestasis
Prevents blood loss
1) vascular spasm
2) platelet plug
3) blood clotting
