tissues chapter 4. what are tissues? groups of cells with the same structure and general function....
TRANSCRIPT
Tissues
Chapter 4
What Are Tissues?
• Groups of cells with the same structure and general function.
• Four types of tissues:
1. Epithelial 2. Connective3. Muscle4. Nervous
• All are surrounded by non-living, intercellular material: MATRIX
Tissue TypesType Description Location
Nervous Excitable cells specialized for rapid communication with other cells
Brain, spinal cord, nerves
Muscular Elongated, excitable cells specialized for contraction
Skeletal, cardiac, and smooth
Connective Lots of matrix, supports, protects and binds together
Tendons, ligaments, blood, cartilage, bone and lymph
Epithelial Little matrix, closely packed, covers surfaces or lines cavities
Epidermis, lining digestive tract, liver and all glands
Epithelial Tissue
• Functions: Covers and protects body surfaces internal and external; secretion, absorption, and excretion.
• Physical Characteristics:- tightly packed, readily divide- anchored by a non-living Basement Membrane to the adjoining tissue layer.
• Lacks blood vessels so nutrients diffuse from adjacent connective tissue
Locations where found:- skin (epidermis)
- Lining of digestive, urinary, reproductive, respiratory tracts.
- Lining body cavities
- Lining fluid filled cavities in brain
- Lining of blood vessels and heart
- Covering organs
“Apical region”
“Basal region”
Classification of Epithelial Tissues
• Number of cell layers:1. simple means a single layer of cells.2. stratified means several cell layers.
• Shape of the cells:1. squamous – flat, tile-like 2. cuboidal – cube shape3. columnar – tall and cylindrical4. transitional – change shape when
under tension
Filtration, osmosis, diffusion
Lung alveoli, capillary walls, lines body cavities
Nuclei are central and round
Secretion and absorption
Kidney tubules, thyroid, and smaller exocrine glands
Absorption, secretion, protection,
Lines digestive tract and uterus
Protection, secretion, mucus movement, Lines respiratory passages
Can be ciliated or have microvilli!
Ciliated!
Protection, secretion, excretion
Skin, oral cavity, throat, anal canal, and vagina.
Lines larger exocrine glands: mammary, sweat, salivary
Protection, secretion, excretion
Distensibility, protection, lines bladder and urethra
Urethra, vas deferens, pharynx
Protection and secretion
Glandular Epithelium
• Most glands are exocrine
• Secrete to internal or external surface
• Exocrine glands have ducts and are lined with simple cuboidal cells.
• Endocrine are ductless and they secrete directly into lymph fluid or bloodstream.
Comparing Endocrine and Exocrine
Type of Exocrine Glands
Connective Tissues
Section 5.3
General Characteristics
• Most abundant tissue in body• Rich blood supply (except for cartilage)• Nerve supply (except for cartilage)• Never exposed to the environment!• 2 Basic Components:
1. Specialized cells
2. Matrix (intercellular material)
a. Ground substance (liquid to solid)
b. Fibers
General Functions
1. Support and protection
2. Binds tissues/organ
3. Transport of materials
4. Store energy
5. Insulation
6. Defense
7. Damage repair
Specialized Cells
• Fibroblasts – most common, secrete fibers and G.S. into matrix. Fiber types:
1. Collagenous (parallel bundles, strength)
2. Elastic (elastin, stretchy, branching)3. Reticular (thin, branching, Basement
Mem.)
• Macrophages – wandering monocytes, phagocytes• Plasma cells – produces antibodies, B-lymphocytes• Adipocytes – cells that store triglycerides (fat molecules)
• Mast cells – large, release Heparin and Histamine substances.
• Melanocytes – production of melanin pigment
Group #1: Connective Tissue
Proper
Areolar (Loose)
Locations: multiple locations including under epithelial tissue of skin, mesentaries
Functions: provides nutrients and support to other tissue types; immune functions; protection
Key Features: loose, scattered fiber appearance, multiple fiber and cell types
Adipose
Locations: subcutaneous region, bone marrow, around viscera and joints, behind eyeball in socket
Functions: lipid storage; thermoregulation; protection (padding)
Key Features: cells with nuclei "pushed to the side"; minimal matrix; white and brown types
Dense or Collagenous
Locations: tendons, ligaments, aponeuroses, sclera (white of eye)
Function: strong support
Key Features: matrix is shiny and white, one fiber type in parallel arrangement; thin fibroblasts; minimal ground substance
Dense (Irregular)Locations: dermis of skin; periosteum, fascia, pericardium, perichondrium and organ capsules.
Function: strong support, resists pulling from all directions
Key Features: thick bundles of fibers with no pattern, minimal ground substance
Group #2: Specialized
Connective Tissues
• Cartilage – Chondrocytes; collagenous fibers, lacunae, and avascular
Types:
1. Hyaline – fine fibers, most common
2. Elastic – thicker with most flexiblity
3. Fibrocartilage – thick collagen fibers
• Bone – osteocytes; mineral deposits and collagen fibers
• Blood – plasma (clear matrix) with formed elements (RBC, WBC, platelets)
Hyaline CartilageLocations: fetal skeleton; covering of bones at joints; ends of ribs, nose, tracheal rings, part of larynx
Function: flexible support, smooth movements at joints
Key Features: bluish/white, glassy appearance; chondrocytes in lacunae
Elastic CartilageLocations: outer ear; epiglottis; eustachian tube, part of larynx
Function: flexible support, strength, maintains shape
Key Features: single chondrocytes in lacunae; random elastic fibers look hairy
FibrocartilageLocations: intervertebral discs, pubis symphysis, meniscus
Function: very firm support, shock absorption
Key Features: collagen fiber bundles, small chondrocytes, no perichondrium
Bone
Locations: all bones, spongy and compact
Function: support, blood cell production, energy storage, protection, levers for muscles
Key Features: rings of bone (Osteons), solid G.S. with minerals, collagen for flexibility
BloodLocations: within blood vessels (arteries, veins, and capillaries), bone marrow, and heart chambers
Functions: transportation of O2 and CO2, immunity, clotting
Key Features: liquid G.S., RBC’s with doughnut appearance, WBC’s have nuclei, platelets tiny fragments