Animal structure and function chap 40 Introduction Anatomy

Animal structure and function (chap 40)

Introduction Anatomy: Biological form Physiology: Biological function Interstitial fluid: Fluid surrounding the cells

Body plan Mouth Gastrovascular cavity Exchange 0. 1 mm (a) An amoeba, a single-celled organism 1 mm (b) A hydra, an animal with two layers of cells

Mouth Food CO 2 Animal body Respiratory system Heart Lung tissue (SEM) Interstitial fluid Nutrients 250 µm Body plan External environment Cells Digestive system Anus Unabsorbed matter (feces) Excretory system Blood vessels in kidney (SEM) Metabolic waste products (nitrogenous waste) 50 µm Lining of small intestine (SEM) 100 µm Circulatory system

Tissues Epithelial Connective Muscle Nervous

Epithelial tissue (epithelium): Covers all surfaces of the body Epidermis (ectoderm): Outer portion of skin Endoderm: Lining of inner surfaces of digestive tract Mesoderm: Inner surface of body cavities

Epithelial tissue Closely packed Tight junctions One/or few cell layers thick Selective absorption in the intestines Rapid gas exchange in lungs Protection from microbes, water loss

Epithelial tissue Regenerative capabilities Liver (gland from epithelial tissues) Epidermis every 2 weeks Stomach lining every 2 -3 days

Epithelial tissue Types Based on cell thickness Shape on exposed surface Simple One layer thick Stratified Multiple layers of cells

Epithelial tissue Shapes of cells Cuboidal: As wide as they are tall (like dice) Columnar: Taller than wide (like bricks on end) Squamous Flat like floor tiles

Epithelial tissues

Epithelial tissue Simple squamous Lining of lungs, capillary walls and blood vessels Simple cuboidal Lining of some glands Simple columnar Lining of stomach, intestines and parts of respiratory tract

Epithelial tissue Stratified squamous Outer layer of skin and mouth Keratin Water resistant protein

Epithelial tissue Exocrine glands (duct system) Duct: Connection from gland to tissue Secrete/absorb chemical solutions Sweat & sebaceous glands Lining of intestines & lungs that secrete mucous

Epithelial tissue Endocrine glands (ductless glands) Hormones Secreted into blood stream

Glands

Connective tissue Holds tissues & organs together Supports, insulates and strengthens Derived from mesoderm Loosely packed cells Scattered in an extracellular matrix

Connective tissue Matrix: Composed of a web of fibers In a foundation of liquid, jellylike or solid Fibers (proteins) are collagen, elastic, or reticular

Connective tissue Collagen: Non-elastic-doesn’t tear easily Elastic: Makes tissue elastic Elastin (protein) Reticular: Thin, branched, joins connective tissue to adjacent tissues

Connective tissue Cells in matrix Fibroblasts: Produce & secrete extracellular matrix Macrophages: Engulf foreign bodies & debris Mast cells & heparin

Connective tissue types 1. Loose connective tissue Beneath skin & between organs Support, insulation, food storage Adipose tissue (fat) Cells become larger when gain weight Shrink with weight loss

Connective tissue 2. Dense connective tissue Tendons, ligaments, sheath around organs (periosteum), dermis of skin Support, strong connections 3. Special connective tissue Cartilage, bone, blood,

Connective tissue

Special connective tissue Cartilage Consists of chondroitin (glycoprotein) & collagen Strong, flexible tissue, absorb stress Joints, ear pinna, nose, intervertebral discs, larynx Chondrocytes: Cartilage cells

Cartilage

Bone Embryos---more cartilage Cartilage is replaced with bone cells or osteocytes Matrix hardens with crystals of calcium phosphate mixed with collagen

Bone Osteoblasts: Lay down new bone Osteoclasts: Dissolve bone Osteons: Unit of bone structure Contains calcified matrix, osteocytes, nerve fibers, blood vessels

Bone Flat bones Long bones Spongy bone: Contains marrow Blood cells formed Compact bone: More dense, gives strength

Bone

Bone

Blood Plasma (matrix) Cells RBC (erythrocytes) Contain hemoglobin (carries oxygen) WBC (leukocytes) Neutrophils, eosinophils, basophils, lymphocytes, monocytes Platelets (thrombocytes)

Blood

Blood Plasma contains Wastes, nourishment Hormones Na+, Ca 2+, other ions Fibrinogen, albumin, antibodies

Connective Tissue Blood Loose connective tissue Plasma White blood cells 55 µm 120 µm Collagenous fiber Cartilage Elastic fiber Fibrous connective tissue Red blood cells 30 µm 100 µm Chondrocytes Chondroitin sulfate 700 µm Adipose tissue Central canal Fat droplets Osteon 150 µm Bone Nuclei

Muscle tissue Movement Organization of actin & myosin filaments Smooth, skeletal & cardiac muscles Striated muscles: skeletal & cardiac Skeletal muscles: voluntary control Smooth & cardiac muscles: involuntary control

Muscle tissue Smooth muscle Walls of blood vessels, stomach, intestines Viscera: Internal organs Made of sheets of cells each with a single nucleus

Muscle tissue Skeletal muscle Attached by tendons to bones Contract move bones

Muscle tissue

Muscle tissue Cardiac muscle Small interconnected cells Linked by gap junctions Openings allow small substances & electrical charges to pass between cells Myocardium Single functioning units

Nerve tissue Neurons Cell body, dendrites, axon Neuroglia Supporting cells Insulate neurons Eliminate foreign bodies

Nerve tissue Dentrites Thin, branched extensions Receive impulses Axons Single extension of cell body Carries impulse away Myelin sheaths, insulating cover

Neurons

Neurons Sensory neurons Eye, ears, surface of skin Motor neurons Brain & spinal cord Interneurons Brain & spinal cord Neurons within the CNS

Neurons

Nervous Tissue Glia Neurons Neuron: Dendrites Cell body Glia Axons of neurons 40 µm Axon (Fluorescent LM) Blood vessel (Confocal LM) 15 µm

Summary Epithelial tissues Simple or stratified Cuboidal, columnar, squamous Connective tissues Loosely packed, tightly packed Special (bone, cartilage, blood) Matrix

Summary Muscle tissues Smooth, cardiac, skeletal Nerve tissues: Neurons (cell body, dentrites, axons) Sensory, motor and interneurons

Coordination Hormones Nervous system Homeostasis

(a) Signaling by hormones STIMULUS (b) Signaling by neurons STIMULUS Endocrine cell Cell body of neuron Axon Nerve impulse Hormone Signal travels everywhere. Signal travels to a specific location. Blood vessel Nerve impulse Axons Response

Homeostasis Dynamic constancy of internal environment Dynamic because conditions fluctuate Narrow range p. H Temp Glucose Oxygen

Regulation 1. Negative feedback loops 2. Positive feedback loops

Negative Feedback

Negative feedback loops Sensors Measure internal environment Integrating center Receives information from sensors Compares to normal range Responds

Negative feedback loops Effectors: Muscles or glands Receive information from center Response

Negative feedback loops Temperature increase Hypothalamus senses deviation Sends signals to relieve heat Sweating & vasodilation Reach baseline Negative feedback stops response

Negative feedback loops Temperature decrease Hypothalamus sends signals Shiver, vasoconstriction Temp to baseline Negative feedback stops response

Thermoregulation

Fig. 40 -9 (a) A walrus, an endotherm (b) A lizard, an ectotherm

Negative feedback loops Glucose (eat a meal) Elevated blood level Islets of Langerhans (sensor, center) Insulin Lowers blood sugar (uptake in muscle, fat & liver cells) Negative feedback stops insulin release

Regulating Blood Sugar

Positive Feedback

Positive feedback loops Uterine contractions Pressure from baby on uterus Causes contractions Causes more stretching More contractions Continues until birth

Positive feedback loop Blood clotting Clotting factors stimulate the formation of more factors Clot forms Maintain blood volume

Bioenergetics Overall flow & transformation of energy in an animal Determines nutritional needs Animal size, activity and environment

Fig. 40 -17 External environment Animal body Organic molecules in food Digestion and absorption Nutrient molecules in body cells Carbon skeletons Cellular respiration Heat Energy lost in feces Energy lost in nitrogenous waste Heat ATP Biosynthesis Cellular work Heat

Metabolic rate Amount of energy an animal uses in a unit of time Torpor: Physiological state of low activity with low metabolism Hibernation: Long term torpor