Animal Organization & Homeostasis 1 Ch. 33 – Animal Organization & Homeostasis

Animal Organization & Homeostasis 2 What are the levels of organization ? What does each level do? Give an example of where you would find each in the human body.

Animal Organization & Homeostasis 3 Levels of Organization Tissue - Group of specialized, but similar, cells performing a common function Organ - Group of tissues performing a specialized function Organ System - Collection of several organs functioning together Organism - A collection of organ systems

Animal Organization & Homeostasis 4 What are the 4 main types of tissue? How does each function? Where might you find these tissues?

Animal Organization & Homeostasis 5 Types of Tissues Four major vertebrate tissue types  Epithelial Covers body surfaces, lines cavities, forms glands  Connective Binds and supports body parts  Muscular Moves the body and its parts  Nervous Receives stimuli and transmits nerve impulses

Animal Organization & Homeostasis 6 Epithelial Tissue Epithelial tissue:  Forms a continuous layer over body surfaces  Lines inner cavities  Forms glands ­ Exocrine glands - Secrete products into ducts or cavities ­ Endocrine glands - Secrete products directly into the bloodstream  Covers abdominal organs

7 Types of Epithelial Tissues in the Vertebrates

Animal Organization & Homeostasis 8 Describe the structure and function of the 3 types of epithelial tissue.

Animal Organization & Homeostasis 9 Epithelial Tissue Three types of epithelial tissues:  Squamous – Flat cells Lining of blood vessels & air sacs of lungs  Cuboidal - Cube-shaped cells Lining of kidney tubules & various glands  Columnar – Pillar-shaped cells Lining of digestive tract & lining of oviducts

10 Types of Epithelial Tissues in the Vertebrates

Animal Organization & Homeostasis 11 1.What is the goal of epithelal tissue? To protect and absorb

Animal Organization & Homeostasis 12 What is the most abundant and widely distributed tissue in animals? Connective tissue What 3 things make up connective tissue?

Animal Organization & Homeostasis 13 Connective Tissue Connective tissue is the most abundant & widely distributed tissue in animal bodies Connective tissues consist of:  Fibroblast cells which are separated from each other by a jelly like matrix containing: 1. collagen fibers--- purpose? 2. elastic fibers---Purpose? 3. Reticular fibers—Purpose?

Animal Organization & Homeostasis 14 How many groups of connective tissue are there?

Animal Organization & Homeostasis 15 Connective Tissue Connective tissues come in four main groups. Each performs a different type of function. 1. Fibrous connective tissue 2. Supportive connective tissues 3. Bone 4. Fluid Connective Tissues What are the functions of each?

Animal Organization & Homeostasis 16 Fibrous Connective Tissue Comes in three main types: 1. Loose fibrous connective tissue  Allows organs to expand (lungs, urinary bladder) 2. Dense fibrous connective tissue  Strong connective tissue ­ Tendons – connect muscles to bones ­ Ligaments – connect bones to other bones at joints 3. Adipose tissue ● Body’s primary energy reservoir ● Also insulates the body ● Contributes to body contours & provides cushioning

Animal Organization & Homeostasis 17 Give an example of how these 3 relate to one another

18 Diagram of Fibrous Connective Tissue

Animal Organization & Homeostasis 19 Supportive Connective Tissues Cartilage  Classified according to type of collagen and elastic fibers found in the matrix  Cartilage cells (chondrocytes), lie in small chambers (lacunae) in the matrix  Cartilage lacks a direct blood supply, thus it heals very slowly.  Found in various locations of body: In nose, ends of long bones & ribs, rings in walls of respiratory passages, fetal skeleton, outer ear, pads between vertebrae & in knee joint

Animal Organization & Homeostasis 20 Why is cartilidge important? What can happen when we lose cartlidge? Does it regenerate? Why or why not?

21 Connective Tissue Examples

Animal Organization & Homeostasis 22 Give me a visual representation of the two types of bone. Compare their similarities.

Animal Organization & Homeostasis 23 Bone Bone is the most rigid connective tissue. Consists of extremely hard matrix of inorganic salts (Ca) deposited around protein fibers, especially collagen. Consists of two types: 1. Compact Bone  Makes up shaft of long bones  Blood vessels in central canal carry nutrients that allow bone to renew itself. 2. Spongy Bone ● Makes up ends of long bones  More open spaces in between solid parts  Still very strong

Animal Organization & Homeostasis 24 Explain how/why blood is a connective tissue

Animal Organization & Homeostasis 25 Fluid Connective Tissues Blood Actually a connective tissue in which cells are embedded in a liquid matrix (plasma). Functions: Transports nutrients and oxygen to cells Removes carbon dioxide and other wastes Types of Cells:  Red blood cells – erythrocytes Transport oxygen molecules around body  White blood cells – leukocytes Fight infection

Animal Organization & Homeostasis 26 Fluid Connective Tissues Other parts of blood: 1.Platelets: ♦ Not complete cells; fragments of giant cells from bone marrow ♦ Form a plug when blood vessels are damaged 2.Lymph: ♦ Fluid connective tissue found in lymph vessels ♦ Absorbs excess tissue fluid & dissolved solutes

Animal Organization & Homeostasis 27 Give an analogy to describe the parts of blood.

28 Blood, a Liquid Tissue

Animal Organization & Homeostasis 29 How can the three types of muscular tissue work together? All muscle tissue contains what two things? Actin and myocin

Animal Organization & Homeostasis 30 Muscular Tissue Composed of cells called muscle fibers. These are contractile cells containing actin and myosin filaments which interact to produce movement. Three types:  Skeletal Muscle ­ Called voluntary muscle because we consciously can tell them what to do. ­ Consists of long, striated cylindrical cells with multiple nuclei. ­ They move body parts. ­ Fast contractions occur.

Animal Organization & Homeostasis 31 Muscular Tissue Smooth Muscle ­ Involuntary muscles. We don’t control consciously. ­ No striations. Shaped like a spindle. Single nucleus. ­ Contract more slowly. ­ Found in walls of organs & blood vessels.  Cardiac Muscle ­ Striated muscle, but mostly involuntary. ­ Cells are cylindrical but with single nucleus. ­ Cells connected end to end at intercalated disks. ­ Makes up wall of heart

Animal Organization & Homeostasis 32 Describe the structure and function of 3 types of muscle cells

33 Muscular Tissue

Animal Organization & Homeostasis 34 What is another name for nerve cells? Neurons

Animal Organization & Homeostasis 35 Nervous Tissue Nervous tissue contains cells called neurons  Made up of three parts:  Dendrites - conducts signals towards cell body  Cell body - contains cytoplasm & nucleus  Axon - process that conducts nerve impulses away from cell body ­ Long axons are covered by myelin, white fatty substance. ­ Outside the brain and spinal cord, fibers bound by connective tissue form nerves

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Animal Organization & Homeostasis 37 Nervous Tissue Nervous system has three functions  Sensory input ­ Sensory receptors detect changes ­ Transmit info to the spinal cord  Data integration ­ Spinal cord and brain integrate ­ Decision is made regarding appropriate response  Motor output ­ Response is transmitted to effector (gland or muscle) ­ Effector initiates actual response

Animal Organization & Homeostasis 38 What supports and services a neuron?

Animal Organization & Homeostasis 39 Nervous Tissue Neuroglia cells outnumber neurons by 50 to 1. They support and nourish neurons. - Most brain tumors involve neuroglia cells.

40 Neurons and Neuroglia

Animal Organization & Homeostasis 41 Describe the structure and function of the skin

Animal Organization & Homeostasis 42 Skin - The largest organ Functions of skin:  Covers and protects underlying body regions - from physical trauma - from pathogen invasion - from water loss  Regulates body temperature, and  Contains sensory receptors - touch, pressure, pain & temperature

Animal Organization & Homeostasis 43 What is the subcutaneous layer of the skin known as? hypodermis

Animal Organization & Homeostasis 44 Skin - The largest organ Regions skin:  Epidermis - Outer, thinner region - Composed of stratified squamous epithelium - New cells are pushed outward, become keratinized (waterproof), and are sloughed off - Melanocytes produce melanin, pigment responsible for skin color - Epidermis helps to produce vitamin D when exposed to sunlight. - Nails grow from specialized epidermal cells

45 Human Skin Anatomy

46 The Epidermis

Animal Organization & Homeostasis 47 Regions of Skin Dermis - deeper & thicker than epidermis, It is a fibrous connective tissue containing elastic and collagen fibers Contains: ­ Hair follicles ­ Sensory receptors ­ Nerve fibers ­ Blood vessels Subcutaneous Layer - Loose, connective tissue located below dermis

48 Human Skin Anatomy

Animal Organization & Homeostasis 49 Organ Systems Body Cavities  Dorsal cavity (toward the back) ­ Contains the cranial cavity and the vertebral canal ­ The brain is in the cranial cavity, and ­ The spinal cord is in the vertebral canal  Ventral cavity (toward the front) is divided by the diaphragm into: ­ The thoracic cavity (includes heart and lungs) and ­ The abdominal cavity (most other internal organs) ­ The pelvic cavity (reproductive & urinary bladder)

50 Mammalian Body Cavities

Animal Organization & Homeostasis 51 Homeostasis The internal environment of an animal’s body consists of tissue fluid, which bathes the cells.  This internal environment tends to be relatively stable over time even while the external environment can change greatly. ­ The maintenance of this stability is termed homeostasis.

Animal Organization & Homeostasis 52 Homeostasis The organ systems of the human body contribute to homeostasis  The digestive system ­ Takes in and digests food ­ Provides nutrient molecules that replace used nutrients  The respiratory system ­ Adds oxygen to the blood ­ Removes carbon dioxide  The liver ­ Store excess glucose as glycogen ­ Later, glycogen is broken down to replace the glucose used ­ The hormone insulin regulates glycogen storage  The kidneys ­ Excrete wastes and salts & help to maintain pH

Animal Organization & Homeostasis 53 Negative Feedback Homeostatic Control  Partially controlled by hormones  Ultimately controlled by the nervous system Negative Feedback is the primary homeostatic mechanism that keeps a variable, such as blood glucose, close to a particular value, or set point. 1. Sensor detects change in internal environment 2. Control center brings about an effect that brings conditions back to normal again.  Sensor no longer activated. Simple negative feedback dampens the original stimulus.

54 Negative Feedback Mechanisms: Simple

55 Negative Feedback Mechanisms: Complex - Heating System

56 Regulation of Human Body Temperature Temperature sensor is located in the hypothalamus of the brain

Animal Organization & Homeostasis 57 Positive Feedback During positive feedback, an event increases the likelihood of another event happening. Examples:  Childbirth Process  Urge to urinate Positive feedback does not result in equilibrium  Does not occur as often as negative feedback  Can actually be harmful, such as when a fever continues to rise to dangerous levels.