Biol 224.3 – Animal Body Systems Lecture Notes PDF

Biol 224.3 – Animal Body Systems Lecture : Organization of Animal Bodies and an Introduction to Nervous Systems Dr Joan Forder Supplementary Reading: Textbook (5th Edition, Chapter 35, page 926-937)...

Biol 224.3 – Animal Body Systems Lecture : Organization of Animal Bodies and an Introduction to Nervous Systems Dr Joan Forder Supplementary Reading: Textbook (5th Edition, Chapter 35, page 926-937) 1 Where we are headed Layers of Organization Animal organ systems Tissue types Epithelial Connective Muscle Nervous Types of Neurons Neuron Structure Glial Cells Why It Matters... In multicellular organisms, cells differentiate into different tissues which combine in different ways to form organs and organ systems with their own unique functions. Such specialization allows multicellular organisms to establish a steady-state internal environment able to be maintained independent of the external environment.  Organization of the Animal Body Cells: Specialized and organized into tissues Tissue: A group of cells with the same structure and function, working as a unit to carry out one or more activities Organ: An assembly of tissues integrated into a structure that carries out a specific function Organ system: A group of organs that carry out related steps in a major physiological process  Coordination of Tissues in Organs and Organ Systems Organ systems perform vital tasks: Acquiring nutrients and other required substances Coordinating their processing, distribution, and disposal Synthesizing molecules Sensing and responding to the environment Protecting the body from injury, disease, and attack Reproducing 11 Major Organ Systems 1. Respiratory 2. Digestive 3. Reproductive 4. Excretory 5. Nervous 6. Endocrine 7. Muscular 8. Skeletal 9. Integumentary 10.Circulatory 11.Immune Fig. 35.9, pp. 936 Fig. 35.9, pp. 937 Organization Example: Digestive System Properties of cells in tissues determine the tissues’ structures and functions Fig. 35.2, p. 927  Animal Tissues Classified as In Digestive System they function as Epithelial Epithelial: protection, transport, secretion, and Connective absorption of nutrients released by Muscle digestion of food Nervous Connective: structural support Muscle: movement Nervous: communication, coordination, and control Epithelial Tissue Consists of sheetlike layers of cells Covers surfaces of body and internal organs Lines cavities and ducts within the body 5 main types of epithelial tissue Epithelial Cell Types 1. Simple Squamous 2. Stratified squamous 3. Cuboidal 4. Single columnar 5. Simple pseuodostratified Fig. 35.4, p. 929 Simple Squamous Epithelium Fig. 35.4a, p. 929 Stratified Squamous Epithelium Fig. 35.4b, p. 929 Cuboidal Epithelium Fig. 35.4c, p. 929 Simple Columnar Epithelium Fig. 35.4d, p. 929 Simple Pseudostratified Columnar Epithelium Fig. 35.4e, p. 929  Exocrine Glands Secretory structures derived from epithelia Exocrine glands Connected to an epithelium by a duct that empties on the epithelial surface Endocrine Endocrine glands Ductless; no direct connection to an epithelium Connective Tissue Consists of cell networks or layers and an extracellular matrix (ECM) Supports other body tissues Transmits mechanical and other forces Sometimes acts as a filter 6 different types of connective tissue  Six Types of Connective Tissues & Their Functions Loose connective tissue Support, elasticity, diffusion Fibrous connective tissue Strength, elasticity Bone Cartilage Movement, support, protection Support, flexibility, low-friction surface for joint movement Blood Adipose tissue Transport of substances Energy reserves, insulation, padding Connective Tissues Fig. 35.6a,b,c,d, p. 932  Muscle Tissue: Vertebrates Skeletal muscle Long contractile cells (muscle fibres) Moves body parts and maintains posture Cardiac muscle Short contractile cells with a branched structure Forms the heart Smooth muscle Spindle-shaped contractile cells Forms layers surrounding body cavities and tubes Nervous Tissue Neurons communicate information between body parts (electrical and chemical signals) Glial cells Support and provide nutrients to neurons Provide electrical insulation between them Scavenge cellular debris and foreign matter Basic Neuronal Structure Fig. 35.8, p. 934  Sensory Neuron Types of Neurons Interneuron Afferent neurons (sensory neurons) Conduct information from sensory receptors to interneurons Interneurons Motor Neuron Integrate the information into a response Efferent neurons (motor neurons) Carry response signals to effectors, which carry out the response  Neuron Structure The dendrites, and often the cell body, receive signals and integrate and transmit them toward the spike initiation zone. Axons Conduct signals away from the spike initiation zone to another neuron or an effector Fig. 42.1, p. 1125  Neural Signals Steps in Processing of Information in Single Neurons Fig. 42.1, p. 1125 A Basic Neuron Circuit An afferent neuron, an interneuron, and an efferent neuron make up a basic circuit. Circuits combine into networks that interconnect the peripheral and central nervous systems. Animal Nervous Systems The functions of the Nervous System result from the activities of only two major cell types: neurons and glial cells. In most animals, these cells are organized into complex networks called nervous systems. In the peripheral nervous system (PNS), the long slender projections of neurons (axons) are bundled into cablelike projections (nerves). Nerves provide a common pathway between different structures and the Central Nervous System (CNS). In the CNS, networks are organized into ganglia and brains. Four Functions of the Animal Nervous System 1. Reception Detection of a stimulus 2. Integration Integrates information to formulate appropriate response 3. Transmission Conducts message along neurons 4. Response Transmits signal to effector organs to produce a response  Astrocyte Glial Cells Astrocytes Help maintain ion balance surrounding neurons Figure 42.3 Oligodendrocytes, Schwann cells Form insulating layers around axons (myelin) Schwann Cell Fig. 42.3, p. 1126 Next Week Membrane potentials Action potentials Synaptic Transmission Post-synaptic Electrophysiology Nervous System Evolution Functional divisions of the vertebrate nervous system