Transcript Connective Tissue
Connective Tissue
• • • Found throughout the body; most abundant and widely distributed of all the tissues Four main types: – – Connective tissue proper Cartilage – – Bone Blood Characteristics: Tissue with large matrix inside of it, rich supply of blood vessels, composed of many types of cells
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Connective Tissue Proper: Areolar
Fibers: collagen, elastic Wraps and cushions all internal organs Attached to all epithelial tissue Dermis: small layer of areolar tissue
Connective Tissue Proper: Dense Regular Tissue
• • • Dense because the collagen fibers are packed together Distinct wave: made to withstand force in one direction Found in tendons and some ligaments and aponeuroses
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Connective Tissue Proper: Adipose
The – “ spaces droplets ” are the cells, with nuclei squished against the sides The clear parts are oil Function: insulation, cushions and protects organs, and reserve fuel Found: under skin in the abdomen, around kidneys & eyeballs, in breasts
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Connective Tissue Proper: Reticular
Provides a framework for white blood cells, mast cells and macrophages = all part of the immune system – Lymphoid organs: spleen lymph nodes and bone marrow
Connective Tissue: Bone
Haversian Canal a series of tubes around narrow channels formed by lamellae Osteoblast Bone forming Cells Osteocyte an osteoblast that has become embedded within the bone matrix, occupying a bone lacuna Lamella Osteoblasts deposit the matrix in the form of thin sheets which are called lamellae.
Canaliculi Canaliculi provide the means for the osteocytes to communicate with each other and to exchange substances by diffusion.
Lacuna In the matrix, osteoblasts become encased in small hollows within the matrix Volkmann ’ s Canal These canals establish connections of the Haversian canals with the inner and outer surfaces of the bone
Bone (osseous tissue)
• • • Compact bone: looks like rings of tree Function: structural support, give body its shape, act as attachment points for muscles Location: bones
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Connective Tissue: Spongy Bone or Cancellous Bone
Doesn ’ t occur in ring shape like compact bone Still has lacuna – *single lacuna spread out Rest of tissue (pink) is called trabeculae
Connective Tissue: Spongy Bone
Red marrow (consisting mainly of hematopoietic) tissue and Red blood cells, platelets and most white blood cells arise in red marrow, found mainly in the flat bones.
Yellow marrow (consisting mainly of fat cells). Yellow marrow is found in the hollow interior of the middle portion of long bones.
Connective Tissue: Hyaline Cartilage
• • • Distinguishing characteristic: – Pairs of lacunae Supports and reinforces structures (like bone), but can bend Found: ends of long bones, connects ribs to sternum, found at end of nose, in trachea and larynx
Connective Tissue: Blood
• • • • Mature red blood cells do not have a nucleus WBC: have a nucleus – Neutrophils and Lymphocyte, monocyte (pictured) Function: transport respiratory gases Location: in blood vessels
Muscle Tissue
• • Highly specialized to contract and produces most types of body movement Three types of Muscle Tissues: – Smooth Muscle – Cardiac Muscle – Skeletal Muscle
Smooth Muscle Tissue
• • • Smooth: no striations Lines hollow structures: – airways to lungs, stomach, intestines, gallbladder, and urinary bladder
Involuntary control:
propels substances along predetermined pathways
Skeletal Muscle
• • • Cells are long, multi nucleated, and striated
Voluntary control
Location: in skeletal muscles attached to bones or occasionally to skin
Cardiac Muscle
• • • • • • Uni-nucleated Intercalated discs allow the cardiac muscle to act as a unit
Involuntary control
Function: propels blood into circulation as it contracts Forms the bulk of the wall of the heart Found: only in the heart
Nervous Tissue
• 2 main cell types found in nervous tissue – Neuroglia: functionally support, protect and insulate neurons and bind them together – Neurons: respond to stimuli and conduct impulses to and from all body organs • Found: Brain, spinal cord, and nerves
Parts of the neuron
• Dendrites: branched processes that receive stimuli and conduct nerve impulses toward the cell body. (input portion of neuron) • Cell body: contains nucleus and specialized organelles • Axon: cytoplasmic extension that conducts nerve pulses away from the cell body. (output)
Integumentary System
• • • Skin (integument) – largest organ of the body Accessory organs: hair, glands, and nails Roles: – Mechanical and chemical protection – Thermal protection – Microorganisms – Prevents water loss – Secretory system (waste products) – Vitamin D synthesis – Cutaneous sense organs
Layers of the skin
• • 2 main layers: – Epidermis: stratified into 4 structural layers (or 5 layers in palms and soles) – Dermis: consists of 2 layers Hypodermis or superficial fascia (subcutaneous layer)- not part of the skin, but binds dermis to underlying organs
Epidermis
Dermis
• • • • Second, deeper part of the skin Composed mainly of connective tissue Blood vessels, nerves, glands, and hair follicles are embedded in the dermal tissue.
Dermis is divided into a superficial papillary region and a deeper reticular region
Dermis
• Papillary region – more superficial dermal layer; in contact with epidermis; – Composed of areolar connective tissue – Dermal papillae –nipple shaped structures indent into the epidermis and contain loops of capillaries. Some dermal papillae contain tactile receptors called corpuscles of touch or Meissener corpuscles [4] which are touch receptors.
– Responsible for fingerprints
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Dermis
Reticular layer of the dermis – Deepest skin layer – dense irregular connective tissue • •
Hypodermis Layer
Subcutaneous layer is deep to the dermis and is not part of the skin Consists of areolar and adipose tissues
Glands of the Skin
• • Several kinds of exocrine glands are associated with the skin Sudoriferous glands or sweat glands empty their secretions onto the skin surface through pores or into hair follicles. Sweat glands: two main types based on their structure, location and type of secretion. – Eccrine and Apocrine
Eccrine Sweat Glands
• • • Simple, coiled tubular glands are much more common than Apocrine Regulate body temperature through perspiration/evaporation Also plays a role in elimination – perspiration is diluted urine
Apocrine Sweat Glands
• • • • Found: skin of axilla, groin, anal regions, areolae areas of the breasts, and bearded areas of the face in men. Begin functioning at puberty. In women cells of apocrine sweat glands enlarge around ovulation and shrink during menstruation Secretions are more viscous (thicker) than eccrine secretions and contain the same compounds as eccrine sweat plus lipids and proteins, pheromones. – Pheromones are chemical signals exuded by many animals - including humans -- that evoke sexual behavior Mammary glands are specialized apocrine glands that secrete milk
Sebaceous glands (oil gland)
• • • • Usually connected to hair follicles Secrete sebum which is a mixture of fats, cholesterol, proteins, inorganic salts and pheromones Sebum coats the surface of hairs and prevents excessive evaporation of water from the skin, keeps the skin soft and inhibits growth of certain bacteria Sebaceous glands are found in the skin all over the body except for the palms of the hands and the soles of the feet. – grasping grip and the traction needed for the soles of the feet would be compromised
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Hair follicle
Hair follicle surrounds the root and consists of columns of dead, keratinized cells bonded together by extracellular proteins – Hair shaft is the superficial portion of the hair, most of which projects from the surface of the skin. – Hair root is the portion of the hair deep to the shaft that penetrates into the dermis and sometimes into the subcutaneous layer. – Arrector pili muscle is the smooth muscle that extends from the superficial dermis of the skin to the side of the hair follicle
• Arrector pili muscle is the smooth muscle that extends from the superficial dermis of the skin to the side of the hair follicle. [14]