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: a sheet-like layer of cells outside of the body or lines organs and cavities; held together by tight junctions. Most frequent site of cancer. Specialized epithelial cells are called glands and they secrete substances out of the cell. Classified as: Simple: single layer of cells Stratified: multiple tiers of cells Types of Epithelial Cells: Cuboidal (cubes)-small tubes of kidney and reproductive tract. Moves materials/absorption. Columnar (columns) lines airways and parts of the gut. Absorption/secretion/protection. Squamous (flat)-lining lungs and blood vessels. Allows substances to diffuse.

Tissues, II 2- Connective: bind and support other tissues; act as shock absorbers; produces red blood cells 3 Kinds: A)Collagenous fibers (strong and stretchy-collagen protein) B)Elastic fibers (stretchy-elastin protein) C)Reticular fibers (provide support-thin branched collagen fibers) Loose connective tissue: binds epithelia to underlying tissue; holds structures together. There are two types: 1. Adipose tissue-aka fat; insulates the body, protects internal organs, and provides a source of energy when necessary. 2. Lymphoid tissue-involved in immune functions; found in lymph nodes, spleen, thymus gland, and red bone marrow Fibrous connective tissue: rigid parallel bundles of cells 1-Tendons- muscles to bones 2-Ligaments- bones to bones; joints Cartilage: collagen in a rubbery matrix (chondroitin); flexible support; no blood supply. Supports soft tissues. Cushions bone ends at joints. Bone: Rigid support; site of muscle attachment; produces blood cells Blood: erythrocytes (RBC’s) carry O2; leukocytes (WBC’s) immunity, Distributes gases/nutrients to cells; removes wastes from them

Tissues, III 3-Nervous: senses stimuli and transmits signals from 1 part of the body to another Neuron: functional unit that transmits impulses Dendrites: transmit impulses from tips to rest of neuron (receive) Axons: transmit impulses toward another neuron or effector (send)

Tissues, IV 4- Muscle: capable of contracting when stimulated by nerve impulses; myofibrils composed of proteins actin and myosin; 3 types: A- Skeletal: voluntary movement (striated)-muscle that pulls on bones B- Cardiac: involuntary: found in the heart (branched striated) C- Smooth: involuntary activities (no striations)-found in the walls of hollow internal organs (stomach, bladder, intestines, and lungs); also lines blood vessels

Organ Systems Digestive-food processing; eliminates food residues Circulatory-transports materials; stabilizes pH and temp Respiratory-gas exchange; helps regulate pH Immune/Lymphatic-defends the body against infection Excretory-removes excess fluid/wastes; osmoregulation Endocrine-hormonally controls body functioning Reproductive-reproduction Nervous-detection of stimuli; coordinates responses Integumentary-protects body from injury/pathogens Skeletal-support; protection; site of muscle attachment Muscular-movement; maintains posture

Internal regulation Interstitial fluid: internal fluid environment of vertebrates; exchanges nutrients and wastes Homeostasis: “steady state” or internal balance Negative feedback: a change triggers a response that counteracts (reverses) the change; 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

Metabolism: sum of all energy-requiring biochemical reactions Catabolic processes of cellular respiration 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)