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BIOL101 Biology A&P Chapter 5
Notes
Introduction
5-1
Chapter 5Lecture Outline
See PowerPoint Image Slidesfor all figures and tables pre-inserted into
PowerPoint without notes.
Copyright (c) The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Objectives: Upon completion of the learning unit, participants will be able to:
• Name the four primary classes into which all adult tissues are classified.
• Name the three embryonic germ layers and some adult tissues derived from each.
• Visualize the three‐dimensional shape of a structure from a two‐dimensional tissue section.
• Describe the properties that distinguish epithelium from other tissue classes.
• List and classify eight types of epithelium, distinguish them from each other, and state where each type can be found in the body.
• Explain how the structural differences between epithelia relate to their functional differences.
• Visually recognize each epithelial type from specimens or photographs.
• Describe the properties that most connective tissues have in common.
• Discuss the types of cells found in connective tissue.
• Explain what the matrix of a connective tissue is and describe its components.
• Name 10 types of connective tissue, describe their cellular components and matrix, and explain what distinguishes them from each other.
• Visually recognize each connective tissue type from specimens or photographs.
• Explain what distinguishes excitable tissues from other tissues.
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• Name the cell types that compose nervous tissue.
• Identify the major parts of a nerve cell.
• Visually recognize nervous tissue from specimens or photographs.
• Name the three kinds of muscular tissue and describe the differences between them.
• Visually identify any type of muscular tissue from specimens or photographs.
• Describe the junctions that hold cells and tissues together.
• Describe or define different types of glands.
• Describe the typical anatomy of a gland.
• Name and compare different modes of glandular secretion.
• Describe the way tissues are organized to form the body’s membranes.
• Name and describe the major types of membranes in the body.
• Name and describe the modes of tissue growth.
• Define adult and embryonic stem cells and their varied degrees of developmental plasticity.
• Name and describe the ways that a tissue can change from one type to another.
• Name and describe the modes and causes of tissue shrinkage and death.
• Name and describe the ways the body repairs damaged tissues.
Histology: study of tissue
Section 1 4 primary tissue classes
Epithelial tissue Connective tissue Nervous tissue Muscular tissue
Section 2 Intercellular junctions Glands and Membranes Tissue growth Development Death
Repair
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Features of Tissue Classes Tissue
Similar cells/cell products Arise from same region of embryo
Differences Type/function Matrix Space of cell/matrix
Matrix = ECF
Fibrous proteins/clear gels Ground substance/ECF Tissue fluid Interstitial fluid Tissue gel
Cartilage/bone → rubbery/stony Matrix > cell/connective tissue Cell > matrix/epithelial/muscle
Embryonic tissue Single cell → many cells → 3 primary germ layers
Ectoderm Epidermis/nervous tissue
Endoderm Mucous membrane
GI tract/respiratory system/digestive Mesoderm→ mesenchyme
Muscle/bone/blood
Tissue Techniques and Sectioning Preparing histological specimens involves special processes for preserving, sectioning, and staining. The goal is to obtain an image that clearly delineates structural details. Usually the specimen is preserved with a fixative such as formalin and sliced into thin sections—one to two cells thick. These sections are stained to show contrast among the different cellular components. They are mounted on slides so they can be observed under a microscope. It is important to remember that sectioning reduces a 3‐dimensional structure to a 2‐dimensional slice—you need to be able to identify the origin of the slice and project it back to the original 3D shape. The 3 types of tissue sections used in the preparation of histological specimens are
Longitudinal section: the tissues are cut along the longest direction of the organ Cross section: the tissue is cut perpendicular to
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length of organ, and Oblique section: the tissues are cut at angle between cross and longitudinal sections
Epithelial Tissue Epithelial tissue
Flat sheet/layers Upper surface → surface/body cavity Lower surface → basement membrane
Anchors epithelium to connective tissue Supplies O2
Simple Epithelia
S. squamous Single row of flat cells Permits diffusion of substances Secretes serous fluid Alveoli, glomeruli, endothelium, and serosa
S. cuboidal S. columnar Pseudostratified columnar
Stratified Epithelia
Stratified St. squamous St. cuboidal St. columnar Transitional epithelium
Stratified squamous epithelia Keratinized epithelium
Apical surface/kertin/retards water loss Nonkeratinized
Moist slippery layer Tongue/oral mucosa/esophagus/vagina
Keratinized → outside body Non‐keratinized → inside body
Stratified cuboidal epithelium 2+ layers Secrete sweat Produce sperm/hormones Sweat glands/ovarian follicles/testes
Transitional epithelium
Multilayered Surface cells stretch/stress
Urinary tract filling/ureter/bladder
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Connective Tissue Most abundant/variable Widely spaced cells Fibrous tissue Cartilage Bone Blood
Functions Connect organs Support/protect physical/immune processes Store energy /produce heat Support body movement Transport materials
Fibers of Connective Tissue Fibrous Connective Tissue
Protein Fibers Collagenous
Tendons/ligaments/deep skin layers
NOTE: Stress that causes tears to this connective tissue produces striae which is commonly referred to as stretch marks
Reticular
Thin/collagenous Spleen/lymph nodes/soft organs
Elastic Stretch/recoil/elasticity Skin/lungs/arteries
Connective Tissue cells and Ground Substance Cells
Fibroblasts Produce fibers/ground substance
Macrophages
Engulf/destroy foreign particles Leukocytes (WBCs)
Support immune function Plasma cells
Immune functions → intestine walls/inflamed tissue Mast cells
Secrete heparin/histamine
Adipocytes
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Fat cells
Ground substance Gelatinous/absorbs force Glycosaminoglycans (GAG)
Regulate water/electrolytes Attract sodium Chondroitin sulfate
Proteoglycans Create bonds Macromolecules—Cellular “glue”
Adhesive glycoproteins Protein‐carbohydrates Bind cell membranes to collagen/other cellular components
Loose fibrous connective tissue Fibrous connective tissue
Loose/dense Loose/ground substance between cells
Areolar Underlies all epithelia Between muscles Passageways/nerves/blood vessels
Reticular
Stroma/lymphatic organs Lymph nodes/spleen/thymus/bone marrow Associated mainly with structure of soft body organs
Adipose/fat
Empty‐looking/thin membranes Energy storage/insulation/cushioning Subcutaneous fatty layer Insulative layer Hibernating animals/newborns have brown fat → heat
Thought question: According to your knowledge of cell mass to cell boundary ration, what do you think is the physiologic significance of brown fat in newborns vs none in adults?
Dense Connective Tissue Fiber between cells
Dense regular
Compressed nuclei
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Closely packed fibers/parallel ↑ tensile strength/Strong! Tendons and ligaments
Injury/stress from wrong direction
Dense Irregular Tissue Few visible cells/random arrangement Withstand stress from multiple directions
Joint capsules/deep skin/around joints/organs
Cartilage Rubbery matrix Chondroblasts produce matrix Cavities/lucunae Surrounded → chondrocytes Avascular/no blood vessels
Diffusion brings nutrients/removes wastes Heals slowly
Types of cartilage vary with fiber types
Hyaline Rubbery matrix Fine collagenous fibers/strong Support airways/larynx/trachea bronchi/fetal skeleton Ease joint movement
Bone ends/moveable joints‐articular cartilage Sterna/ribs
Elastic cartilage
Conspicuous elastic fibers External ear/epiglottis
Fibrocartilage Extensive collagenous fibers No sheath/perichondrium Great tensile strength ↑ stress areas/body
Pubic symphysis Meniscus Intervertebral discs
Bone Spongy/compact Spongy
Network/struts/support Covered/compact bone Head of long bones
Compact
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Solid/complex Vertical blood vessels/long bone See again/bony tissue
Matrix → concentric lamellae around central canal
Osteocytes/mature bone cells Occupy lacunae Skeletal support Muscle leverage
Mineral storage Blood
Fluid tissue Liquid matrix/plasma 3 cell types
Red blood cells/carriers White blood cells/fighters Blood platelets or thrombocytes/clotters
RBCs/No nuclei WBCs/prominent nuclei
In heart/blood vessels
Nerve Tissue Large cells/long processes Neurons/neuroglial cells
Neurons Cell body/soma Dendrites/axon Transmit outgoing signals/impulses
Neuroglial
No process Support neuron function Internal communication Nerves/nervous systems Ganglia
Study nerve tissue CNS/PNS/ANS
Muscle Tissue Elongated cells/contract Exert force
Move limbs Push blood Expel urine
Types
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Skeletal Long cylindrical cells Attached to bone Multinucleated/striated/voluntary
Cardiac muscle In heart/striated/involuntary
Smooth muscle Short fusiform cells Nonstriated/involuntary One central nucleus In viscera/iris/hair follicles/sphincters Involved in swallowing GI tract functions labor contractions Erection of hairs Airflow/pupil control
Intercellular Junctions Anchor cells
Three important junctions are: Tight junctions
Zipper‐like Little matrix No easy passage Protects/invaders Prevents leakage
GI/Urinary Desmosomes
Form a patch/”snap‐like” Cytoplasmic intermediate filaments attach cells Terminate inside cell/protein plaque In uterus/heart/epidermis of skin
Gap junctions
Ring/transmembrane proteins Water‐filled channel/sells Solutes pass from cell to cell In embryos/cardiac/smooth muscle
Intercellular communication!
Glands Endocrine
Ductless Secrete hormones into blood
Exocrine Duct
Simple/compound Drainage cells/acinus Function cells/parenchyma
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Secretions Enzymes/sweat/mucus
Endocrine vs. Exocrine Not clear cut! Glands secrete → ducts AND into blood stream Organs with glandular component (Brain) Body control
Nervous system: Rapid response/short‐lived Endocrine system: Slower response/long‐acting
Types of Secretions Glands/secretions
Serous glands → thin, watery Sweat/milk/tears/digestive juices Mucous glands → produce mucin Absorbs water → sticky secretion/mucus
Mixed glands → mixture of both Cytogenic
Example: Release whole cells Gametes: sperm/egg
Secretion Methods/Holocrine Gland How secretion produced
Holocrine glands Secretory cells disintegrate → product Oil‐producing glands/scalp
Merocrine glands → exocytosis/importing Tears/gastric glands/pancreatic glands Specialized merorcine gland/apocrine gland Mammary glands/armpit sweat glands Viscous/regions with hair
Primarily merocrine
Mucous Membranes Membranes
Cutaneous/skin Dry/protects external surface Internal epithelial membranes
Mucous Epithelium Lamina propria
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Muscularis mucosae Line passageways to exterior
Reproductive/respiratory Urinary/digestive systems
Traps/removes foreign particles/bacteria Columnar tissue
Goblet cells/mucous Cilia to move mucous
Serous
Simple squamous epithelium/areolar tissue Produces serous fluid Covers organs Lines cavity walls
Synovial Lines some joint cavities Connective tissue Secretes synovial fluid
Tissue Growth Vocabulary! (Talk the talk!) Hyperplasia Tissue growth → cell multiplication Cellular mass ↑/↑ number/cells
Hypertrophy Enlargement /preexisting cells Mass ↑/cell size ↑ Muscle growth → hypertrophy exercise
Neoplasia
Growth/ tumor/abnormal tissue
Changes in Tissue Types Tissue type change
Differentiation Unspecialized embryo tissue → specialized mature tissue Mesenchyme → muscle
Metaplasia
Mature tissue from one type to another Simple cuboidal tissue before puberty → Stratified squamous after puberty
Stem Cells Undifferentiated cells/plasticity Can produce several types of mature cells
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2 types Embryonic
Early human embryo Totipotent (can differentiate) Pluripotent (limited differentiation)
Adult
Undifferentiated cells in adult tissue Multipotent (early stages) Unipotent (can produce 1 cell type) Plasticity lost
Tissue Repair Regeneration
Damaged cell replaced/same type cell Skin/liver
Fibrosis Damaged cell replaced /scar tissue Function not restored Muscle injury/scarring of lung tissue/severe cuts/burns
MI/damaged cells replaced by scar tissue Loss of pumping ability Stromal cells used not parenchymal Severe fibrosis/keloids
Large raised shiny scars
Tissue Engineering Artificial production of tissues/organs Human implanting
Seeding with human cells Grow in “bioreactor” Used in human Significant progress
Skin grafts/heart valves/coronary vessels and bones Research continues Liver can regenerate
Healing of a Laceration Healing process Damage
Blood vessels rupture Leak blood Cells leak histamine → dilates blood vessels →
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↑ blood flow → ↑ capillary permeability Plasma brings antibodies/clotting factors WBCs join/phagpcytize
Blood clots gather/form scab/surface Macrophages phagocytize New capillaries grow/wound Fibroblasts deposit new collagen (2 wks) Epithelial cells grow/close wound Scab falls off Epithelium thickens/regenerates Connective tissue below forms scar/fibrous tissue Remodeling/2 yrs Final Summary A Rapid Review! 4 primary tissue classes
Epithelial—cells that cover body surfaces/inside and out Connective tissue—largest/most diverse
Blood /bone It connects
Nervous tissue Muscular tissues—3 basic types: skeletal, smooth and cardiac Cell junctions
Tight junctions/little matrix between layers Limits/stops movement between layers Gap junctions allow communication/ movement
Glands
Endocrine glands/ductless Exocrine glands have ducts—passageways from gland → target areas
Body membranes Outer epithelial/cutaneous membrane –the skin Internal membranes—
Mucous/ serous/ synovial membranes Tissue growth/development/repair
Stages of tissue repair Fibrosis → scarring (stroma cells) Regeneration → functional tissue (parenchyma cells)
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Coming next → The Integumentary System