Lab 1 ANIMAL TISSUES
Levels of Organization Animals are multicellular heterotrophs whose cells lack cell walls. Most animals exhibit a hierarchical level of organization: Cells are organized into tissues Tissues combine to form organs Organs comprise organ systems
What is a tissue? Group of similar cells that perform a specialized function. Examples include: Bone tissue Blood tissue Muscle tissue
4 basic types of animal tissue: Epithelial Connective Muscle Nervous
Characteristics: Epithelial Tissue Cells fit closely together forming continuous sheets Apical (free) surface covers body surface or lines interior of organs Basal surface adheres to the basement membrane
Epithelial Tissue Supported by connective tissue Avascular, but innervated Have remarkable powers of regeneration Variety of functions depending on type (protection, absorption, filtration, excretion, secretion)
Epithelial Tissue Classification based on # of cell layers and shape of cells on apical surface. # of Cell Layers: Simple one layer of cells Stratified two or more layers Pseudostratified simple, but appears stratified
Epithelial Tissue Cell shape on apical surface: Squamous flattened & scale-like Cuboidal box-like Columnar tall & column-like
Characteristics: Connective Tissue Most are well vascularized Consists of widely-spaced cells and fibers embedded in a non-living extracellular matrix Variety of functions depending on type (support, binding other tissues, transport, defense, storage)
Characteristics: Well vascularized Muscle Tissue Packed with actin & myosin filaments Function to contract producing most types of body movements
Characteristics: Nervous Tissue Composed of two types of cells: Neurons specialized to generate and transmit impulses; amitotic Neuroglia (glial cells) protect, support & insulate neurons Main component of the nervous system (brain, spinal cord & nerves)
This week s lab is devoted to histology (the study of tissues).
Exercise A: Epithelial Tissues Simple squamous epithelium Location alveoli of lungs, lining of heart & blood vessels Function allows diffusion of materials surface view lateral view
Exercise A: Epithelial Tissues Simple cuboidal epithelium Location kidney tubules & ducts; ovary surface Function secretion & absorption simple cuboidal epithelium basement membrane cross section longitudinal section
Exercise A: Epithelial Tissues Simple columnar epithelium Location lines digestive tract from stomach to the rectum Function absorption & secretion
Exercise A: Epithelial Tissues Pseudostratified columnar epithelium Location lining of trachea & upper respiratory tract Function secretion & propulsion of mucus ciliated cell cilia goblet cell basal cell basement membrane connective tissue
Exercise A: Epithelial Tissues Stratified squamous epithelium Location keratinized type: epidermis of skin non-keratinized type: linings of esophagus, mouth & vagina Function protection stratified squamous epithelium Keratinized connective tissue Non-keratinized
Exercise B: Connective Tissues Loose (areolar) connective tissue Location widely distributed under epithelia Function cushions organs Gel-like matrix Collagen fiber Fibroblast nucleus Elastic fiber
Exercise B: Connective Tissues Adipose Location under skin; around kidneys & eyeballs; in breasts Function supports & protects organs; insulates against heat loss; provides reserve fuel
Exercise B: Connective Tissues Dense (fibrous) connective tissue Location tendons & ligaments Function attaches muscle to bone (tendons) & bone to bone (ligaments)
Exercise B: Connective Tissues Hyaline cartilage Location covers ends of long bones; nose, trachea & larynx Function support & reinforcement Chondrocytes sitting in lacunae (cavities) Matrix packed with collagen fibers
Exercise B: Connective Tissues Bone Location bones Function support & protection; calcium storage; provides levers for muscles to act on; site of blood cell production Canaliculi Central canal Osteocyte sitting a in lacuna (cavity) Osteon
Exercise B: Connective Tissues Blood Location contained within blood vessels Function transport of gases (O 2 & CO 2 ), nutrients & metabolic wastes Red blood cells Platelet White blood cells: neutrophil monocyte lymphocyte Plasma (liquid matrix)
Exercise C: Muscle Tissues Skeletal muscle Long, cylindrical, multinucleate cells with obvious striations Location attached to bones or occasionally to skin Function voluntary movement Nuclei Striations
Exercise C: Muscle Tissues Cardiac muscle Branched, uninucleate cells with striations Location walls of the heart Function contract involuntarily to propel blood Branched cell Intercalated disc Striations
Exercise C: Muscle Tissues Smooth muscle Tapered, uninucleate, non-striated cells Location walls of hollow organs Function contract involuntarily to propel materials along internal passageways Circular layer Nuclei Longitudinal layer Individual muscle cell
Exercise D: Nervous Tissue Neurons cell body contains nucleus cytoplasmic processes: dendrites transmit impulses to cell body axon transmits impulses from cell body Neuronal processes (axons & dendrites) Neuron nucleus Neuron cell body Neuroglia