Chapter 40 – An Introduction to Animal Structure and Function

Tissues: groups of cells with a common structure and function (4 types) Anatomy: structure Physiology: function 1- Epithelial: outside of body and lines organs and cavities; held together by tight junctions basement membrane: dense mat of extracellular matrix, an attachment membrane Glandular epithelia: absorb or secrete chemicals, ex. mucous membrane Classifying epithelial tissue, by number of cell layers and shape of cells: Simple: single layer of cells Stratified: multiple tiers of cells Pseudostratified: single layer, but appears stratified Cuboidal: dice-like Columnar: like bricks on end Squamous: like floor tiles

Epithelial Tissue examples Stratified Columnar – urethra Simple columnar – intestines Pseudostratified columnar – mucus membranes of respiratory tract Stratified squamous – skin, esophagus, anus Simple squamous – blood vessels Cuboidal – kidney tubules and glands

Connective Tissue 2- Connective: bind and support other tissues; sparce cells scattered throughout a matrix Made from 3 different types of fibers: Collagenous fibers: collagen protein, most abundant, non-elastic, do not tear easily Elastic fibers: elastin protein, rubbery and flexible Reticular fibers: thin branched fibers, join connective tissue to adjacent tissues Six major types of connective tissue: Loose connective tissue – binds epithelia to underlying tissue, holds organs Fibrous (dense) connective tissue – parallel bundles of cells; tendons (muscle to bone) and ligaments (bone to bone) Bone – mineralized tissue by osteoblasts (bone forming cells) Cartilage – collagen in a rubbery matrix; chondrocytes; strong and flexible Adipose tissue – fat storage, insulation, and protection Blood – liquid plasma matrix; erythrocytes (RBCs) carry oxygen, leukocytes (WBCs) immunity, thrombocytes (platelets) blood clotting

Connective Tissue Fibroblasts – secrete the protein ingredients of the extracellular fibers Macrophages – amoeboid cells that roam the maze of fibers, engulfing foreign particles and dead cell parts from phagocytosis

Muscle and Nervous Tissue 3-muscle tissue: composed of long muscle fibers capable of contracting when stimulated by nervous impulses Myofibrils – contracting unit made of actin and myosin 3 types of muscle tissue: Skeletal – voluntary, striated Cardiac – involuntary, branch-striated, heart Smooth – involuntary, no striations 4-nervous tissue: senses stimuli and transmits signals from 1 part of the animal to another Neuron: functional unit that transmits impulses Dendrites: transmit impulses from tips to rest of neuron Axons: transmit impulses toward another neuron or effector

Muscle and Nervous Tissue

Organ systems Organ: organization of tissues Digestive-food processing Circulatory-internal distribution Respiratory-gas exchange Immune/Lymphatic-defense Excretory-waste disposal; osmoregulation Endocrine-coordination of body activities Reproductive-procreation Nervous-detection of stimuli Integumentary-protection Skeletal-support; protection Muscular-movement; locomotion Organ: organization of tissues Mesentaries: suspension of organs (connective tissue) Thoracic cavity (lungs and heart) Abdominal cavity (intestines) Diaphragm (respiration) Organ systems…...

Organ Systems

Metabolism: sum of all energy-requiring biochemical reactions Catabolic processes of cellular respiration Calorie; kilocalorie/C Endotherms: bodies warmed by metabolic heat Ectotherms: bodies warmed by environment Basal Metabolic Rate (BMR): minimal rate powering basic functions of life (endotherms) Standard Metabolic Rate (SMR): minimal rate powering basic functions of life (ectotherms)

Thermoregulation Ectotherm – gain heat from environment Endotherm – use metabolic heat to regulate body temperature; can sustain vigorous activity, live on land, but energetically expensive Poikilotherm – internal temp varies widely Homeotherm – stable internal temps

Energy Budgets Blue = basal standard metabolism Orange = temperature Brown = growth Yellow = activity Red = reproduction

Thermoregulation - external Radiation – indirect transfer of heat between objects, absorbing heat from sun Evaporation – removal of heat from the surface of a liquid Conduction – direct transfer of heat between molecules Convection – transfer of heat by movement of air or water past a surface

Thermoregulation - internal Interstitial fluid: internal fluid environment of vertebrates; exchanges nutrients and wastes Homeostasis: “steady state” or internal balance Negative feedback: change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation; i.e., body temperature Positive feedback: physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change; i.e., uterine contractions at childbirth