Animal Tissues andOrgan Systems

Chapter 20

Key Concepts

• Types of tissues– Four tissues types organized into organs

• Epithelial• Connective• Muscle• Nervous

• Organ systems– Three embryonic tissues are source of all

adult organs– Each organ system has specialized

function

Stem Cells

• Undifferentiated cells with potential to develop into many cell types– Embryonic stem cells,

more versatile– Adult stem cells, less

versatile

Body Organization

• Tissue– Group of cells performing same task

• Organ– Two or more tissues performing same task

• Organ system– Two or more organs performing same task

Tissues

• Groups of cells and intercellular

substances that interact in one or more

tasks

• Example: muscle tissue

Organs

• Group of tissues organized to perform a task or tasks

• Example: Heart is an organ that pumps blood through body

• Heart consists of muscle tissue, nervous tissue, connective tissue, and epithelial tissue

Organ Systems

• Groups of organs that interact

physically and/or chemically to perform

a common task

• Example: Circulatory system includes

heart, arteries, and other vessels that

transport blood through the body

Homeostasis

• Stable operating conditions in the internal environment

• Brought about by coordinated activities of cells, tissues, organs, and organ systems

4 Types of Tissues

• Epithelial tissues

• Connective tissues

• Muscle tissues

• Nervous tissues

Type 1: Epithelial Tissues

• Sheet-like, line body surfaces,

cavities, ducts, and tubes

• One free surface faces a body fluid or

the environmentsimplesquamousepithelium

basementmembrane

connective tissue

Glands

Secretory organs derived from epithelium

• Exocrine glands have ducts or tubes– Salivary and sweat glands– Secrete to the OUTSIDE

• Endocrine glands are ductless– Adrenals and pituitary – Secrete to the INSIDE

exo = out endo = in

Type 2: Connective Tissues• Most abundant tissues in the body

• Different types– Soft

• Beneath skin, encapsulates organs– Specialized

• Cartilage• Bone• Adipose (fat)• Blood

• Fibroblasts– Secrete “ground substance” forming

polysaccharides– Secrete collagen, the most abundant protein in the

human body

Soft Connective Tissues• Loose connective tissue

• Dense, irregular connective tissue

• Dense, regular connective tissue

red blood cell

white blood cell

platelet

Fig. 20-3g, p.342

Type 3: Muscle Tissue

• Cells contract when stimulated

• Moves body and specific body parts

• 2 types, 3 classes– Striated

• Skeletal• Cardiac

– Not striated • Smooth

Skeletal Muscle

• Attaches to and moves bones

• Long, cylindrical cells

• Striated cells

• Voluntary control

nucleus

Cardiac Muscle

• Present only in heart

• Cells are branching– Ends joined by

communication junctions

• Cells striated

• Not under voluntary control

where cells meet

Smooth Muscle

• Located in soft internal organs and blood vessels

• Cells taper at ends

• Cells not striated

• Not under voluntary control

cell nucleus

Type 4: Nervous Tissue• Detects stimuli, integrates information,

and relays commands for response

• Consists of excitable neurons and supporting neuroglial cells

Neurons

• “Excitable” cells

This means that:

• Stimulus sends electrical impulse along plasma membrane because of specific proteins

This allows the cells to:

• Transmit information to other neurons, muscles or glands

11 Major Organ Systems

• Integumentary

• Nervous

• Muscular

• Skeletal

• Circulatory

• Endocrine

• Lymphatic

• Respiratory

• Digestive

• Urinary

• Reproductive

I promise that you will be tested on these 11 systems. At the very least, you will need to know the functions of each system. All of this info is on page 344.

Nervous System

Muscular System

Skeletal System

Circulatory System

Endocrine System

Fig. 20-6, p.344a1

Integumentary System

11 Major Organ Systems

Lymphatic System

Respiratory System

Digestive System

Urinary System

Reproductive System

Fig. 20-6a2, p.344

11 Major Organ Systems

Skin: An Organ SystemIntegumentary

• Epidermis: Stratified epithelium

• Dermis: Dense connective tissues

• Hypodermis: Loose connective tissue and adipose tissue

Functions of Human Skin

• Protects body from injury, dehydration, UV radiation, and some pathogens

• Helps control temperature

• Receives external stimuli

• Involved in vitamin D production

Important stuff, this

Sun Damages Skin

• UV light stimulates melanin production– tans skin

• Tan protects inner layers against UV damage

• UV exposure causes– elastin fibers to clump– skin to age prematurely– skin cancer

The Epidermis is an Epithelial Tissue

Porphyria and vampirism

Where do Tissues and Organ Systems Come From?

Primary Tissues

Three primary tissues in vertebrate embryos give rise to all adult tissues:

Ectoderm

Mesoderm

Endoderm

ecto=out meso=middle endo=inside

Primary Tissues (cont’d)

• Ectoderm– Outer layer of skin– Nervous tissue

• Mesoderm– Muscles, bones and most of the

circulatory, reproductive and urinary systems

• Endoderm– Lining of the digestive tract, as well as the

liver, lungs and pancreas

5 Major Body Cavities

• Cranial cavity

• Spinal cavity

• Thoracic cavity

• Abdominal cavity

• Pelvic cavity