Lecture 3: Connective Tissue Flashcards
Overview
- widely distributed in the body
- cells are not stacked tightly, they are spaced well apart
- supporting tissue composed of cells embedded within a matrix that varies in consistency from fluid to crystals
- cells are responsible for synthesis and maintenance of the extracellular fluid
examples: cartilage, bone, ligaments, blood, and adipose tissue
connective tissue subtypes: 3 types
structural, defensive, and sequestering
structural connective tissue
fibroblast, cartilage, bone
defensive connective tissue
macrophages, lymphocytes
sequestering connective tissue
adipose tissue, red blood cells
fibroblasts
most common connective tissue within vertebrate bodies
flat, irregular, branching cells
secretes structurally strong proteins into matrix between cells; most commonly COLLAGEN
-fibroblasts also secrete elastin
Elastin
fibrous tissue that is the principal component of the lungs
Areolar (loose) Connective Tissue (ACT)
- found throughout the body wherever protective cushioning and flexibility are needed
- ie. blood vessels are surrounded by a sheath of ACT; permits the vessels to move and yet protects them
- also present beneath the skin, attaching it to underlying muscles
Dense Regular CT
present in tendons, connecting muscle to bone, and in ligaments, connecting bone to bone
Dense Irregular CT
present in dermis (living part) of the skin
- arranged in thick mat
- tanned to make leather, also present in arterial walls
Cartilage: 3 types
firmer and flexible tissue that does not stretch, yet not as hard as bone
- laid down along lines of stress; cells=chondrocytes
- 3 types: hyaline, elastic, and fibrocartilage
hyaline cartilage
- glass-like covering of bones within joints
- forms a smooth surface that reduces friction so one bone easily glides over another
- found at ends of long bones
elastic cartilage
mixture of cartilage substances and elastic fibers
-found in external ear
fibrocartilage
cartilage and collagen
-interverteral discs are made of fibrocartilage
Bone
special form of cartilage where the collagen fibers are coated with a calcium phosphate salt
-bone forming cells are osteoblasts and osteoid tissue, that calcify to form bone
harvesian canals
channels surrounded by lamellae, which contain blood vessels and nerve cells
lamellae
bone laid down in concentric layer
spongy or cancellous bone
lines the medullary cavity
compact bone
surrounds the spongy bone and collagen fibers are laid down in a pattern far denser than the interior framework
Blood
connective tissue consisting of microscopically visible elements: erythrocytes, leukocytes, and platelets/thrombocytes, all suspended in intercellular fluid called plasma
plasma>erythrocytes>leukocytes
plasma
complex fluid in which blood cells and thrombocytes circulate
- 93% water, 7% solutes, including proteins, inorganic solutes, nonprotein oranic substances (glucose, glycerol, and fatty acids)
- hormones, enzymes, vitamins, and pigments
- cell waste products (urea, uric acid)
- amino acids
serum
supernatant yellow fluid that is expressed out when blood coagulates
-serum is used for prevention and treatment of diseases because it contains the antibody fraction of the blood
Blood cell types
red blood cells/erythrocytes, white blood cells/leukoccytes, and platelets/thrombocytes
RBC
transport gases
- flat discs with a central depression
- contain pigment called hemoglobin, which associates and dissociates with O2 and CO2
WBC, 2 types
granular leukocytes (granulocytes), and Agranular leukocytes (agranulocytes) -both are the defense against invading bacteria and other foreign substances
Granulocytes: 3 subtypes
neutrophils, eosinophils, and basophils
Neutrophils
first line of defense against bacteria
-very motile phagocytic
eosinophil
detoxification of foreign proteins and substances
- less motile phagocytic
- found in lungs mammary glands, and small intestine
Basophil
- inflammatory response
- cytoplasmic granules contain heparin (anticoagulant) and histamine (vasodilator) outside blood
Agranulocytes: 2 types
-monocytes and lymphocytes
Monocytes
- largest leukocytes
- precursor of macrophage; defend against microorganisms and chemicals
lymphocytes
B-lymph=antibody-user
T-lymph=celllular immune response
Adipose tissue aka fat
forms when connective tissue cells take up fat for storage as inclusions within the cytoplasm of cells
-most fat of animal body is white in color, may be yellow due to presence of carotene in feed
brown fat
- present in hibernating and young animals
- generates heat to protect young mammals and awakening hibernating mammals from extreme cold
Smooth muscle:
involuntary, visceral, and unstriated
- spindle shaped cells that contain one centrally located nucleus per cell
- found in the walls of digestive tract, blood vessels, urinary and reporductive organs
- contract more slowly than striated muscles and respond to a variety of stimuli
Striated muscle
voluntary, skeletal
- long fibres: striations, many peripherally located nuclei; posses cell membrane=sarcolemma
- each striated muscle has its own nerve supply: all or none law
- striated muscle tissue + some connective tissue makes up the flesh of meat producing animals
Cardiac muscle
- involuntary, striated
- modified muscle cells called Purkinje’s fibres conduct impulse within the heat
- intercalated discs increase the speed of electrical transmission between muscle fibres
Nerve cells consist of
dendrites, conducting impulses towards cell body
- nerve cell body
- nucleus
- axons, conducting impulses away from cell body
