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2 General Characteristics1. Embryologic origin – develop only from mesoderm 2. the connective tissues consist of cells and intercellular matter secreted by the cells 3. connective tissues are highly vascularized 4. generally function to connect and support the other tissues of the body
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4 Classification of Connective Tissues1. based on the type of cell or cells 2. based on the type of intercellular matter found between the cells
5 Types of Connective Tissue1. Areolar (Loose) Connective Tissue a. cells present (1) fibroblasts - principal type of cell - secrete proteins into the spaces between the cells (2) macrophages – big eater, swallow bacteria, viruses engulf foreign agents
6 (3) mast cells – secrete histamine & other chemical mediators of inflammation
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11 Local Inflammation (1) local dilation of blood vessels = erythema(in the injured area) (2) local increased permeability of blood vessels = swelling (edema) - more leaky (3) local stimulation of pain fibers = pain
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13 b. intercellular matter (1) protein gel (much like “Jello”) containing protein fibers (a) collagen protein fibers – confer strength to the tissue (b) elastin protein fibers – confer elasticity to the tissue (2) All proteins are synthesized and secreted by the fibroblasts
14 c. Areolar connective tissue is the most widely distributed tissue in the body serving to support and nourish (via the blood vessels) the other tissues of the body
15 Adipose (Fat Tissue) Cells present- closely packed adipose (fat) cells, each containing a large fat-filled vacuole b. Intercellular Matter: - small amount of protein fibers, secreted by the fat cells c. Adipose tissue provides a reservoir of food (for energy), insulates against heat loss, supports and protects the organs it encloses
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17 Fat Tissue (Adipose) Location (1) under the skin (subcutaneous fat)(2) around the kidneys and eyeballs (3) buttocks and breasts Fat cells secrete a little bit of collagen
18 3. Dense Fibrous Connective Tissuea) cells present - fibroblasts b) intercellular matter - principally collagen protein fibers, secreted by the fibroblasts, which confers strength to the tissue c) there are 2 sub-types of Dense Fibrous Connective tissue based upon how the protein fibers are arranged
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20 Dense Fibrous Connective TissueIs simpler than areolar connective tissue Contains fibroblasts and collagen
21 2 types of Dense Fibrous Connective Tissue1. Dense Regularly-Arranged Fibrous Connective Tissue – collagen is arranged in one direction so it means it is really strong in one direction 2. Dense Irregularly-Arranged Fibrous Connective Tissue – the collagen is running all around so it is relatively strong in all directions
22 Dense Regularly-Arranged Fibrous Connective Tissue
23 Dense Irregularly-Arranged Fibrous Connective Tissue
24 (1) Regularly Arranged Dense Fibrous Connective Tissue(a) the protein fibers are arranged in parallel bundles (b) locations: (1) tendons – cords that connect muscles to bones (2) ligaments – cords that connect bones together * it is the collagen that makes them strong
25 Other locations for regularly arranged dense fibrous connective tissue(3) dura mater – fibrous connective tissue that encloses the brain and spinal cord - tough mother - it is one of the layers around the brain and spinal cord (4) fascia – fibrous connective tissue that encloses muscles (5) perichondrium and periosteum – fibrous connective tissue that encloses cartilage and bones
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31 Irregularly Arranged Dense Fibrous Connective Tissue(a) the protein fibers are interwoven, running in all directions (b) location: (1) dermis of the skin (2) scar tissue
32 Scar Tissue
33 Stratified Squamous Epithelium
34 Stratified Squamous Non Keratinized Epithelium
35 Stratified Squamous (Keratinized)
36 4. Cartilage – unusual connective tissue - no blood vessels, that is why they do not heal very well a. cells present: - chondrocytes, usually arranged in groupings of 2 to 4 cells, surrounded by a pocket of fluid called a lacuna b. intercellular matter: - protein gel (much like “Jello”) containing protein fibers
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38 c. cartilage contains no blood vessels (non-vascular), and is thus an exception to the general pattern of connective tissue d. cartilage tissue is capable of growing in both length and width (thickness) e. there are 3 sub-types of cartilage (based upon the nature of the intercellular matter):
39 (1) Hyaline Cartilage (a) the intercellular matter is made up of a gel membrane with collagen protein fibers (secreted by the chondrocytes) (b) locations (1) the embryonic lung bones of the body (2) front of the nose (3) the trachea & larynx
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41 (2) Fibrocartilage (a) the intercellular matter is made-up of a gel containing large bundles of collagen protein fibers (b) locations: - the intervertebral disks
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43 (3) Elastic Cartilage (a) the intercellular matter is made up of a gel containing elastin protein fibers (b) locations – the external ear * Hardest is bone followed by fibrocartilage
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45 Bone Tissue a. cells present- osteocytes, each surrounded by a pocket of fluid called a lacuna b. intercellular matter: (1) calcium salts (calcium phosphate & calcium carbonate) or (Ca(PO4)2 & CaCO3) (2) collagen protein fibers interwoven in the calcium salts
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47 c. bone tissues are highly vascularizedd. bone tissue is only capable of growing in width (thickness) e. there are 3 subtypes of Bone Tissue (based upon its organization):
48 a. Compact Bone – need to recognize under a microscope- the osteocytes are arranged in concentric circles, called Haversian Systems b. Spongy (Cancellous) Bone Tissue - the osteocytes are arranged in a spongy network
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51 2 types of Bone Cells Calcitonin – Osteoblasts (Osteocytes) – secrete calcium mineral = form bone tissue (ossification) Parathyroid Hormone – Osteoclasts – break-down calcium mineral = they dissolve bone tissue = Bone Resorption
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53 * Enamel of a tooth – hardest substance in the body* In real life if you break a bone, it bleeds * When a woman reaches 50, the ovaries stop working, the ovaries stop secreting estrogen - the osteoblasts would secrete less calcium but the osteoclasts would still breakdown calcium
54 Bone Tissue Picture
55 Femur Bone Picture
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57 Histology Art (Bone)
58 Histology Art (Bone)
59 Compact Bone Picture
60 Spongy (Cancellous) Tissue
61 Bone is strong but not that strong wherein we cannot move anymore that is why we have compact and spongy parts of a bone
62 Tibia Picture
63 Tibia
64 Ends of a bone – Epiphysis ( E means ends)Shaft of the bone – Diaphysis
65 The long bone is covered with periosteum
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67 Periosteum – covering of the bone- regularly arranged dense fibrous connective tissue Compact bone where bone cells (osteocytes) are arranged in concentric rings
68 Haversian system picture
69 Haversian canal picture
70 f. General Structure of BonesThe types of bones: A. long bone B. short bone C. flat bone D. irregular bone
71 Pictures of long bones
72 Picture of short bone (phalanges)
73 Flat bone (skull bone) – occipital bone
74 Irregular bone (Vertebra)
75 Structures of Long Bones(a) Diaphysis – shaft of the bone (b) Epiphysis (1) proximal epiphysis (2) distal epiphysis (3) epiphyseal plates (line) – location of ossifying cartilage prior to completion of bone growth
76 (c) Medullary (Marrow) Cavity(1) Red Marrow – filled with bunch of blood, actively producing blood cells (2) Yellow Marrow – filled with fat and not producing blood cells * Red marrow is found at the epiphyseal ends of long bones such as femur
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80 By the time you are 26-25 – it is now filled with yellow marrowSternum, vertebrae, ribs – filled with red marrow until adulthood Limbs – 20-25, marrow cavities become fatty
81 Structure of a Flat Bone (picture of parietal bone)
82 Picture of parietal boneWith outer compact bone and inner spongy bone
83 Histological picture of flat boneThese are the parts (periosteum, compact bone, spongy (cancellous) bone
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85 Embryologic development of bones(1) Long Bones: Endochondral Bone Formation Picture
86 Long Bones develop out of cartilage
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88 (2) Flat Bones: intramembranous bone formation picture
89 (1) Long Bones (a) mesodermal cells – all connective tissues come from mesoderm (b) cartilage (Hyaline) or chondrocytes (c) middle of the humerus – starts to change to bone tissue (picture) - primary ossification center (d) an artery would grow into the primary ossification center
90 (e) the diaphysis becomes bone tissue – the primary and distal ends would become bone tissue or now becomes the secondary ossification center - the last remaining parts would be hyaline cartilage – are now called epiphyseal plates or growth plates * Bone grows in width and cartilage grows in length and width
91 Bones of the epiphysis and diaphysis picture
92 Epiphyseal plates or growth plates picture
93 It is the hyaline cartilage that allows us to grow taller, once the hyaline cartilage would change in our body we can no longer grow
94 Pictures of Zone of resting cartilageZone of proliferating cartilage – growth zone Zone of hypertrophic cartilage
95 2 hormones stimulate the growth of cartilage at the epiphyseal plates(1) growth hormone (2) testosterone – promotes lengthening of the bone that is why men are generally taller than women (example brother and sister)
96 X-ray picture of a femur, tibia
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98 Adult – femur is thicker/widerChild – looks like broken in the tibia as well as the femur, that is where cartilage is, x-rays go through cartilage and not bone
99 If parents are concerned about their child is not growing anymore the medical doctors would look into the cartilage, then if he if there is little cartilage then they would measure the growth hormones If you see growth plates, you would know that the person is a child
100 (3) Flat Bones – Intramembranous Bone FormationWhat will become skull bone starts out as mesodermal cells or mesenchymal cells – becomes fibroblasts – secrete collagen protein – dense fibrous connective tissue – fibroblasts and collagen – then starts ossification turning into bone In summary – mesodermal cells – fibroblasts – ossification – bone tissue
101 Fetal skull – fontanels – made up of dense fibrous connective tissueWhat is the difference between flat and long bones?
102 Long bones – mesoderm – cartilage – bone – endochondral bone formationFlat bones/skull bones – mesoderm – fibrous connective tissue – bone The difference is cartilage or fibrous connective tissue in the intermediate stage
103 By the time children are 2 years old they pretty much have a hard skull
104 (4) Hemopoietic Tissues: Blood and Lymph(a) cells present: (1) Red Blood Cells (Erythrocytes) - transport oxygen and carbon dioxide (2) White Blood Cells (Leukocytes) (a) produce antibodies and interferon that inactivate foreign agents (b) phagocytic (engulf) foreign agents (3) Blood platelets - produce thromboplastin which triggers blood clotting
105 (b) intercellular matter: Plasma(1) water (92%) (2) plasma proteins (7%) - most synthesized by liver cells
106 Blood is cells and the stuff between cells is plasma
107 Tumors (Neoplasms) A. Types 1. Benign Tumors – increased multiplication of tissue cells 2. Malignant Tumors (cancers) a. characteristics (1) increased multiplication of tissue cells (2) the abnormal cells exhibit metastasis (migration)
108 B. treatment: (1) surgery (2) radiation (3) chemotherapy
109 We categorized cancer based on the tissue where they come fromCarcinoma – cancer coming from epithelial tissues and this is where most cancers originate Leukemia – from white blood cells Sarcoma – cancer that originates from connective tissues