ANIMALS Structure and Function

Unifying Themes in Animal Anatomy and Physiology There is a correlation between form and function. The comparative approach allows us to see how species of diverse evolutionary history and varying complexity solve problems common to all. Animals have the capacity to respond and adjust to to environmental change in two temporal scales. –Long term adaptation. –Short term – physiologic responses.

Tisssue Groups of Cells With Common Structures and Functions Four types of tissue 1.Epithelial 2.Connective 3.Nerve 4.Muscle

Epithelial Form- sheets of tightly packed cells Function – cover the outside of body, line organs and body cavities Categorized by the number and shape of the free surface cells –Simple – one layer of cells –Stratified – multiple layers of cells –Psuedostratified – one layer but appears to be multilayer because cells are different lengths –Cell shape – cubodial, columnar or squamous

Some Tissues Are Specialized in Absorption or Secretion Some ciliated – lining of respiratory system Some are mucous membranes – line nasal and oral cavity Structure fits forms –Example: simple squamous epithelium is leaky and specialized for diffusion

Connective Tissue Form -characterized by a sparse cell population scattered through an extensive extracellular matrix Function – to bind and support tissue Three types –Collagen – tensile strength (resists stretching) –Elastic fibers – long thread s of protein –Reticular fibers – prolonged to form connections to adjacent tissue

Types of Connective Tissue Loose connective tissue ( has all three types of fibers) Adipose tissue – fat storage (each cell has one large fat droplet) Fibrous connective tissue- tendons and ligaments

Types of Connective Tissue Cartilage – skeleton of all vertebrate embryos Bone - mineralized Blood – composed of plasma, leukocytes, erythrocytes and platelets ( made in the marrow)

Nerve Tissue Form – neurons that are specialized to conduct an impulse of bioelectric signal Function – senses stimuli and transmits signals from one part of the animal to another

Muscle Tissue Form – parallel bundles of microfilaments made of the contractile proteins, actin and mycin Funtion - long excitable cells capable of contraction Most abundant tissue in most animals Three types of muscle

Types of Muscle Striated – responsible for voluntary movements. Cardiac – forms the contractile wall of heart. Smooth – unstriated and is found in walls of organs and is responsible for involuntary movement.

Systems are interdependent: an organism is a living whole greater than the sum of its parts.

Animals are hetrotrophs that harvest chemical energy from the food they ingest.

Animals Have a Range of Metabolic Rates Minimum – support basic life functions Maximal – occur during peak activity Determined by measuring –Oxygen used for cellular respiration –Heat loss per unit of time Metabolic rate per gram is INVERSELY related to body size among similar animals

Endotherms –Generate own body heat –Require more kilocalories than ectotherms –Many are homeothermic –Bird and mammals –BMR kcal/day – men kcal./Day-women Ectotherms –Acquire most of body heat from environment –Include fish, amphibians, reptiles and invertebrates –SMR (standard metabolic rates) must be determined at a specific temperature

FUEL MANAGEMENT Monomers of any complex organic molecule can be used for fuel. CH 2 O and fats are used first. Oxidation of fat liberates 9.5 kcal/gram (twice that of CH 2 O or protein) Excess food taken in is stored as –Glycogen in the liver and muscles –Fat in adipose tissue

When the diet is deficient in calories Glycogen is used first Fat Body protein (results in muscle atrophy and can even result in consumption of brain proteins) Diet must supply carbon and nitrogen necessary for biosynthesis of other organic molecules.

Essential amino acids are those that must be obtained from the diet. Human adults can synthesis 12 of the 20 amino acids. Protein deficiency results when the diet lacks one or more of the amino acids. Humans can not store amino acids therefore a deficiency results in the retardation of protein synthesis

Other Essential Nutrients Essential fatty acids – unsaturated fatty acids that can not be produced by the body – usually not a problem Vitamins

Feeding Adaptations Suspension feeders – sift small particles from water –Clams, oysters, baleen whales Substrate feeders-live in or on food and eat through it –Leaf miners Deposit feeders-ingest partially decayed organic materials with substrate –Earthworms Fluid feeders-suck nutrient rich fluid from a living host –Tick, aphids, leech, hummingbirds, bees Bulk feeders – eat relatively large pieces of food

Intracellular – vacuoles –Sponge – only intracellular digestion Extracellular – occurs within compartments that are continuous with the outside of the body –Simple body plan – gastrovascular cavity –Complete digestive track or alimentary canal

Four Main Stages of Ingestion Digestion –Enzymatic digestion cleaves into monomers –Mechanical fragmentation Absorption elimination

Digestive Enzymes EnzymeLocationFunction Salivary amylase Gastric Juice Pepsin Pancreatic amylase Pancreatic lipase Trypsin & chymotryosin