Biology Sylvia S. Mader Michael Windelspecht Chapter 31 Animal Organization and Homeostasis Lecture Outline Copyright © The McGraw-Hill Companies, Inc

BiologySylvia S. Mader

Michael Windelspecht

Chapter 31 Animal Organization and

HomeostasisLecture Outline

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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31.1 Types of Tissue

• Tissues are: Collections of specialized cells organized to

perform a common function

The four tissue types are:

Epithelial Connective Muscular Nervous

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Types of Tissue

• Epithelial Tissue (epithelium) Forms a continuous layer over body surfaces Lines body cavities Forms glands Epithelial cells may be connected to one another by

• Tight junctions• Adhesion junctions• Gap junctions

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Functions of epithelial tissue include:

ProtectionSecretionAbsorptionExcretionFiltration

3 types of epithelial tissue

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1. Simple

2. Stratified

3. glandular

Types of Tissue

• Simple Epithelia - A single layer of cells

Classified according to cell type:

• Squamous epithelium – flattened cells• Cuboidal epithelium – cube-shaped cells• Columnar epithelium – cells resembling columns

Glandular Epithelia

• - Secretes a product A gland can be a single epithelial cell or can contain

many cells Exocrine glands - Secrete products into ducts or

cavities Endocrine glands - Secrete products directly into the

bloodstream

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Stratified Epithelia –

Layers of cells

Types of Epithelial Tissues in the Vertebrates

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Simplesquamous

Simple cuboidal

basement membranebasement membrane

• lining of lungs, blood vessels• allows diffusion

• lining of kidney tubules, various glands• absorbs molecules

(All): © Ed Reschke

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Types of Epithelial Tissues in the Vertebrates

cilia

Simple columnar• lining of small intestine, oviducts• absorbs nutrients

Pseudostratified,ciliated columnar• lining of trachea• sweeps impurities toward throat

Stratified squamous• lining of nose, mouth, esophagus, anal canal, vagina• protects

basement membrane

basementmembrane

goblet cellsecretesmucus

goblet cellsecretesmucus

basementmembrane

(All): © Ed Reschke


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• Connective tissue functions: Establishing a structural framework Transporting fluids and dissolved materials Protecting delicate organs Supporting, surrounding and interconnecting

tissues Storing energy reserves Defending the body from microorganisms

• Connective tissue: Specialized cells Ground substance - Noncellular material Protein fibers

• Collagen fibers - contain collagen providing strength and flexibility

• Reticular fibers – contain thinly branched collagen fibers

• Elastic fibers – contain elastin

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Three categories of connective tissueFibrous

Supportive

Fluid

Types of Connective Tissue in Vertebrates

15(a, b); (c): © The McGraw-Hill Companies,Inc. Dennis Strete, Photographer

Loose fibrousconnectivetissue

fibroblast

a.

elasticfiber

collagenfiber

b. c.

nucleus

50 µm 400xcollagen

fibersnuclei of

fibroblasts

Adiposetissue

Dense fibrousconnectivetissue

50 µm

• has collagenous fibers closely packed.• in dermis of skin, tendons, ligaments.• functions in support.

• cells are filled with fat.• occurs beneath skin, around heart and other organs.• functions in insulation, stores fat.

• has space between components.• occurs beneath skin and most epithelial layers.• functions in support and binds organs.


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Types of Connective Tissue in Vertebrates

(d, e): © Ed Reschke

Hyalinecartilage

Compact bone

osteoncentral canal

d. e.

320xchondrocytewithin lacunae matrix

50 µmosteocyte

within a lacunacanaliculi

• has cells in lacunae.• occurs in nose; in the walls of respiratory passages; at ends of bones, Including ribs.• functions in support and protection.

• has cells in concentric rings.• occurs in bones of skeleton.• functions in support and protection.


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Fibrous Connective Tissue consist of:

• Fibroblast cells

• A matrix containing collagen and elastic fibers

Loose fibrous connective tissue• Allows organs to expand

Adipose tissue• Stores energy

• Insulates the body and provides padding

Dense fibrous connective tissue• Strong connective tissue

• Tendons – connect muscle to bone

• Ligaments – connect bones to other bones at joints

Diagram of Fibrous Connective Tissue

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Blood vessel

Adipose cell:stores fat

Groundsubstance: fillsspaces betweencells and fibers

Elastic fiber:branched andstretchable

Stem cell: divides toproduce other typesof cells

Collagen fiber:unbranched, strongbut flexible

Fibroblast: divides toproduce other typesof cells

Reticular fiber:branched, thin, andforms network

White blood cell:engulfs pathogensor produces antibodies

Cartilage• Classified according to type of collagen and elastic fibers

found in the matrix (hyaline cartilage, elastic cartilage, fibrocartilage)

• Cartilage cells lie in small chambers (lacuna) in the matrix

Bone• Matrix is inorganic salts deposited around protein fibers

• Bone cells are located in lacunae

• Lacunae arranged in concentric circles within osteons around tiny tubes (central canals)

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Supportive Connective Tissue

Blood• A connective tissue in which cells are embedded in a liquid

matrix (plasma)– Red blood cells – oxygen transport– White blood cells – immune response– Platelets – involved in the clotting process

• Functions– Transports nutrients and oxygen to cells– Removes carbon dioxide and other wastes

Lymph• A fluid connective tissue located in lymphatic vessels

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Fluid Connective Tissues

Blood, a Liquid Tissue

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b. Blood smear

plasma

white blood cell

platelets

red blood cell

plasma

white blood cells(leukocytes)

red blood cells(erythrocytes)

a. Blood sample after centrifugation

Muscular (contractile) Tissue

Contractile cells containing actin and myosin filaments Cells are called muscle fibers Three types of muscle tissue:

• Skeletal Muscle– Voluntary - Long, striated fibers, multinucleated

• Smooth (visceral) Muscle– Involuntary - No striations

• Cardiac Muscle– Striated, but mostly involuntary– Cells are bound to each other by intercalated disks– Relies on pacemaker cells for regular contraction

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Muscular Tissue

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Cardiac muscleSkeletal muscle Smooth muscle

400 250nucleus

nucleusnucleus

a.

striationintercalated disksmooth muscle

b. c.

• has striated cells with multiple nuclei.• occurs in muscles attached to skeleton.• functions in voluntary movement of body.

• has spindle-shaped cells, each with a single nucleus.• cells have no striations.• functions in movement of substances in lumens of body.• is involuntary.• is found in blood vessel walls and walls of the digestive tract.

• has branching, striated cells, each with a single nucleus.• occurs in the wall of the heart.• functions in the pumping of blood.• is involuntary.

a, c: © Ed Reschke; b: © McGraw-Hill Higher Education, Dennis Strete, photographer

cell

Nervous system (functions):

Sensory input• Sensory receptors detect changes• Transmit information to the spinal cord and brain

Data integration• Spinal cord and brain integrate data• Decision is made regarding appropriate response

Motor output• Response is transmitted to effector (gland or

muscle)• Effector initiates the actual response

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Nervous Tissue

Conducts electrical impulses

Conveys information from one area to another

Nervous tissue includes:• Neurons

– Transmit information

– Consist of dendrites, a cell body, and an axon

– Outside the brain and spinal cord, fibers bound by connective tissue form nerves.

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Neuroglia• Support and nourish neurons

• Neuroglia in brain include– Microglia

– Astrocytes

– Oligodentrocytes

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Nervous Tissue

Neurons and Neuroglia

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axon

cell body

axon

a. Neuron and neuroglia

dendrite

Neuronnucleus

MicrogliaAstrocyte

Oligodendrocyte

myelin sheath

Capillary

b: © Ed Reschke


b. Micrograph of a neuron 200×

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Regenerative Medicine

• In humans, axons outside the brain and spinal cord can regenerate, but not those inside these organs.

• Injured neurons in CNS degenerate Permanent loss of nervous function.

• In cold-water fishes and amphibians axon regeneration in the CNS does occur. Several proteins play role in axon

regeneration

Creating a New Type of Salamander for Limb Regeneration

31.2 Organs, Organ Systems, and Body Cavities

• Organ Composed of two or more tissue types

working together for a particular function

• Organ System Composed of various organs that cooperate

to carry out a general process• Ex: the digestion of food

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Body Cavities

1.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

2. Ventral cavity (toward the front) is divided into

• The thoracic cavity (includes heart and lungs),

• The abdominal cavity (most other internal organs), and

• The pelvic cavity (certain reproductive organs)31

Mammalian Body Cavities

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diaphragm

a.

Cranialcavity:contains brain

DorsalcavityVertebral

cavity:containsspinal cordThoracic

cavity:contains heart,lungs, andesophagus

Abdominalcavity:contains stomach,liver , spleen,pancreas,and intestines

Ventralcavity

Pelviccavity:contains certainreproductiveorgans

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Mammalian Body CavitiesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

b.

Thoracic cavity:contains esophagus,heart, and lungs

Abdominal cavity:contains digestive and other organs

Pelvic cavity:contains reproductiveand other organs

31.3 The Integumentary System

• Functions of skin Covers and protects underlying body regions

Regulates body temperature, and

Contains sensory receptors

• Skin and its derivatives make up the integumentary system

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Regions of the Skin

Epidermis Dermis Subcutaneous Layer

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- Outer, thinner region

Stratified squamous epithelium

New cells are pushed outward, become keratinized, and are sloughed off

Melanocytes produce melanin (pigment)

UV radiation can cause mutations in the DNA of skin cells, leading to skin cancer.

Dermis - Deeper and thicker than epidermis

• Fibrous connective tissue containing elastic and collagen fibers contains:

– Receptors

– Nerve fibers

– Blood vessels

Subcutaneous Layer - Loose, connective tissue located below dermis

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The Integumentary System• Accessory Structures of Human Skin:

Nails

Hair follicles

Hair follicles

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Nails

Grow from nail root and form protective covering of distal portion of fingers and toes

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Hair follicles

Begin in the dermis and continue through the epidermis

Contain oil glands (sebaceous glands) which secrete sebum

Lubricates the hair within the follicle as well as the skin

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Hair follicles

Begin in the dermis and continue through the epidermis

Contain oil glands (sebaceous glands) which secrete sebum

Lubricates the hair within the follicle as well as the skin

Human Skin Anatomy

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Dermis

Epidermis

Subcutaneous layer

nerve

arteryvein

adipose tissue

sensory receptor

hair root

sweat gland

arrector pili muscle

oil gland

free nerve endings

hair shaft

hair follicle

melanocytes

capillaries

sweat pore

The Epidermis

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Ep

ider

mis

a. Photomicrograph of skin c. Melanoma

Der

mis

flattened anddead cells

cells undergoingkeratinization

b. Basal cell carcinoma

stem cellsand melanocytes

dermalprojection

a: © John D. Cunningham/Visuals Unlimited; b: © Ken Greer/Visuals Unlimited; c: © James Stevenson/SPL/Photo Researchers, Inc.

31.4 Homeostasis

• The organ systems of the human body contribute to homeostasis:

The ability of an organism to maintain a relatively constant internal environment

Animals vary to the degree in which they can regulate internal variables.

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The organ systems of the human body contribute to homeostasis

1.The digestive system• Takes in and digests food• Provides nutrient molecules that replace used nutrients

2.The respiratory system• Adds oxygen to the blood • Removes carbon dioxide

3.The liver and the kidneys• Store excess glucose as glycogen• Later, glycogen is broken down to replace the glucose used• The hormone insulin regulates glycogen storage

4.The kidneys• Under hormonal control as they excrete wastes and salts

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Homeostasis

• Homeostatic Control

Partially controlled by hormones

Ultimately controlled by the nervous system

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Negative feedback is the primary homeostatic mechanism that keeps a

variable close to a set value

• Sensor detects change in environment

• Regulatory center initiates an action to bring the conditions back to normal

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Regulation of Room Temperature Using Negative Feedback

stimulus

stimulus

Homeostasistoo cold

too hot

Control center

68°F set point

Sensor

Sensor

68°F set point

sends data tothermostat

directs furnaceto turn off

negative feedbackand return tonormal temperature

70Ftoo hot

negative feedbackand return tonormal temperature

directs furnaceto turn on sends data to

thermostat

66°Ftoo cold

furnace off

furnace on

Control center


Regulation of Body Temperature by Negative Feedback

Control center

Control center

Sensor

SensorEffect

Effect

stimulus

stimulus

Normal body temperature

above normal

below normal

98.6F set pointsends data tocontrol center

directs responseto stimulus

Blood vessels dilate;sweat glands secrete.

negative feedbackand return to normaltemperature

negative feedbackand return to normal

Blood vessels constrict;sweat glands are inactive.

directs responseto stimulus sends data to

control center

98.6F set point


Positive feedback

• is a mechanism that brings about an ever greater change in the same direction Childbirth process

• Positive Feedback Does not result in equilibrium Does not occur as often as negative feedback

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Positive FeedbackCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

uterus

pituitary gland

2. Signals cause pituitary gland to release the hormone oxytocin. As the level of oxytocin increases, so do uterine contractions until birth occurs.

1. Due to uterine contractions, baby’s head presses on cervix, and signals are sent to brain.

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Biology Sylvia S. Mader Michael Windelspecht Chapter 31 Animal Organization and Homeostasis Lecture Outline Copyright © The McGraw-Hill Companies, Inc