Anatomy and Physiology I Lab BSC 2085L Laboratory 2

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Anatomy and Physiology I LabBSC 2085LLaboratory
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• Cell Cycle
• Introduction to Tissues
• Integumentary System

Associate Professor Pamela L. Pannozzo pannozzp_at_pb
cc.edu
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The Cell Cycle

• Most cells reproduce through cell division,
  called mitosis
• Cells go through a reproductive cycle controlled
  by proteins
• 2 Cell Cycle Phases
• 1. Interphase
• 2. Mitosis

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Cell Cycle

• Interphase
• Growth (G1), synthesis (S), growth (G2)
• Mitotic phase
• Mitosis and cytokinesis

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Interphase

• The period from cell formation to cell division
  divided into three subphases
• G1 (growth 1) metabolic activity and vigorous
  growth
• G0 cells that permanently cease dividing
  (neurons, skeletal muscle cells)
• S (synthetic) DNA replication
• G2 (growth 2) preparation for division

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Mitosis

• The phases of mitosis are
• Prophase
• Disintegration of nuclear envelope, chromatids
  condense, spindle fibers attach to centromeres
• Metaphase
• Chromatids pushed to middle of cell
• Anaphase
• Chromatids pulled to opposite poles
• Telophase
• Nuclear envelopes form
• Chromatids unwind
• Cytokinesis
• Cleavage furrow forms
• Cells split

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Introduction to Tissues

• Groups of cells similar in structure and function
• Four types of tissues
• Epithelial
• Connective
• Muscle
• Nerve

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Epithelial Tissue

• Closely packed cells
• No blood vessels
• Arranged in sheets
• Free surface
• bottom surface
• Reproduce rapidly
• Cover organs and line body cavities

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Epithelial Tissue

• Types of cells
• Squamous
• Cuboid
• Columnar
• Number of layers of tissue
• Simple
• Pseudostratified
• Stratified

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Functions of Epithelial Tissue

• Protecting underlying structures
• Acting as barriers
• Permitting the passage of substances
• Secreting substances
• Absorbing substances

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Classification of Epithelia by Shape

• Squamous, cuboidal, or columnar

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Simple Squamous
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Simple Squamous (cont.)
Kidney (Glomerulus)Simple squamous epithelium
lines the glomerulus. The nuclei are blue.
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Simple Cuboidal

• Single layer of cubelike cells with large,
  spherical central nuclei
• Function in secretion and absorption
• Present in kidney tubules, ducts and secretory
  portions of small glands, and ovary surface

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Simple Columnar
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Simple Columnar Epithelium
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Pseudostratified Columnar
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Transitional

• Several cell layers, basal cells are cuboidal,
  surface cells are dome shaped
• Stretches to permit the distension of the urinary
  bladder
• Lines the urinary bladder, ureters, and part of
  the urethra

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Transitional Epithelium
Urinary BladderThe expandable stratified
epithelium of the bladder is referred to as
transitional epithelium. Note that its surface
cells are large rather than flattened as in
stratified squamous epithelium.
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Stratified Squamous

• Thick membrane composed of several layers of
  cells
• Function in protection of underlying areas
  subjected to abrasion
• Forms the external part of the skins epidermis
  (keratinized cells), and linings of the
  esophagus, mouth, and vagina (nonkeratinized
  cells)

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Stratified Squamous Epithelium
VaginaNote that the connective tissue underlying
the epithelium (lightly stained area in middle)
extends into the epithelium as "peg-like"
structures.
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Connective Tissue

• Found throughout the body
• Most abundant tissue
• 4 Types
• Connective Tissue Proper
• Areolar, Adipose, Reticular, Dense Fibrous
• Cartilage
• Bone
• Blood

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Functions of Connective Tissue

• Enclosing and separating as capsules around
  organs
• Connecting tissues to one another as tendons and
  ligaments
• Supporting and moving as bones
• Storing as fat
• Cushioning and insulating as fat
• Transporting as blood
• Protecting as cells of the immune system

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Connective Tissue Proper Areolar
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Areolar Connective Tissue
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Connective Tissue Proper Adipose
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Connective Tissue Proper Reticular
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Connective Tissue ProperDense Fibrous
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Dense Irregular Connective Tissue
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Organ Systems The Integumentary System
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Integumentary System

• Consists of
• Skin, Hair, Nails, Glands
• Functions
• Protection
• Sensation
• Temperature regulation
• Vitamin D production
• Excretion

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Skin

• Two parts
• Dermis
• Epidermis
• Epidermis
• Stratified squamous epithelial cells
• 30-45 layers
• Rapid mitotic rate
• 4 weeks for cells to move through layers
• Dermis
• Areolar dense fibrous connective tissue
• Blood vessels, hair follicles, glands

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Epidermis and Dermis
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Epidermal Cells

• Cell types
• Keratinocytes Produce keratin for strength
• Basal cells Produce epidermal cells
• Melanocytes Contribute to skin color
• Merkels cells Detect light touch and pressure
• Langerhans cells Immune system macrophages
• Keratinization Cells die and produce outer layer
  of keratin protein that is water-resistant and
  resists abrasion, forming permeability layer

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Epidermal Strata 4 layers

• Stratum Basale
• Deepest portion of epidermis 1 cell layer
• High mitotic activity
• Stratum Spinosum
• Limited cell division, cells begin producing
  keratin
• 8-10 layers of cells
• Stratum Granulosum
• In superficial layers nucleus and other
  organelles degenerate and cell dies, filled with
  keratin
• 3-5 layers of cells
• Stratum Corneum
• Most superficial, flattened dead keratin-filled
  cells
• 15-30 layers of cells
• Slough off in 2 weeks

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Epidermal Layers and Keratinization
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Dermis

• Provides strength
• Papillary layer
• Areolar connective tissue
• Superior end folded into dermal papillae
• Capillaries involved in temperature homeostasis
• Reticular layer
• Dense fibrous connective tissue
• Major blood vessels, hair follicles, glands

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Hypodermis

• Deep to the dermis
• Also called subcutaneous layer, attaches skin to
  muscles
• Areolar adipose connective tissue
• Types of cells
• Fibroblasts
• Adipose cells
• Macrophages

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Accessory Skin Structures

• Hair
• Found everywhere on human body except palms,
  soles, lips, nipples, parts of external
  genitalia, and distal segments of fingers and
  toes
• Glands
• Sebaceous or oil glands
• Sudoriferous or sweat glands

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Hair Structure

• Composed of shaft and root
• Shaft protrudes above skin surface
• Root located below surface and base forms the
  hair bulb
• Arrector pili Muscle contraction causes hair to
  stand on end

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Glands

• Sebaceous glands
• Oily secretions
• Empty onto skin surface and hair follicles
• Sudiferous glands
• Merocrine glands
• Water and salts,perspiration
• Empty onto body surface
• Apocrine glands
• Proteins and fats
• Empty onto hair follicles in axillary and genital
  areas
• Possible chemical signalling

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Sensory Receptors

• Pacinian corpuscles
• Sense deep pressure and vibration
• Located in hypodermis
• Meissners corpuscles
• Sense light touch
• Located in epidermis