Upload
others
View
20
Download
0
Embed Size (px)
Citation preview
1
Chapter 4: Body Organization & Homeostasis
BIO 105
Organization of the body
Tissues
A tissue is composed of a group of similarly
specialized cells that work together to perform some common function.
Four tissue types:
Epithelial, Connective, Muscle, Nervous
Epithelial Tissue Characteristics
• Organized into sheets of cells
• Covering & lining
• Glands
• Apical & basal surfaces
• Basement membrane
• Functions?
2
epithelial tissueSIMPLE EPITHELIUM
Simple squamous
• One layer of flattened cells• Located in air sacs of lungs, heart and blood
vessel linings• Allows exchange of nutrients, gases, and wastes
epithelial tissueSIMPLE EPITHELIUM
Simple cuboidal• One layer of cube-shaped cells
• Located in linings of kidney tubules and glands
• Functions in absorption and secretion
epithelial tissue
SIMPLE EPITHELIUM
Simple columnar• One layer of tall, slender cells
• Located in lining of gut
• Functions in absorption and secretion
3
epithelial tissueSTRATIFIED EPITHELIUM
Stratified squamous• Several layers of flattened cells• Located on surface of skin, lining of mouth, esophagus,
anus, and vagina• Provides protection against abrasion, infection, and drying out
e
4
Glands
A gland consists of one or more cells that
secrete the cell product into a duct, onto a
surface, or into the blood.
• Endocrine vs. exocrine glands
Characteristics of Connective Tissue
• Most abundant and widespread
• Binds, supports, anchors
• Cells & extracellular matrix (ECM)
• Consistency of ECM ground substance varies
connective tissueCONNECTIVE TISSUE PROPER
Areolar connective tissue• Widely distributed; found under skin,
around organs, between muscles• Wraps and cushions organs
5
connective tissueCONNECTIVE TISSUE PROPER
Adipose (fat) tissue• Found under skin, around kidneys
and heart• Functions in energy storage and insulation;
cushioning for organs
connective tissueCONNECTIVE TISSUE PROPER
Dense connective tissue• Found in tendons and ligaments• Forms strong bands that attach bone to muscle or bone to bone
connective tissueSPECIALIZED CONNECTIVE TISSUE
Cartilage• Found in rings of respiratory air tubes,external ear, tip of nose
• Provides flexible support; cushions
connective tissueSPECIALIZED CONNECTIVE TISSUE
Bone
• Found in the skeleton
• Functions in support, protection(by enclosing organs), and movement
6
connective tissueSPECIALIZED CONNECTIVE TISSUE
Blood• Found within blood vessels• Transports nutrients, gases, hormones, wastes;
fights infections
Muscle Tissue
• Muscle tissue can contract and shorten
• There are three types of muscle tissue:Skeletal muscle• Long cylindrical striated
cells with many nuclei
• Voluntary contraction
• Most are found attached
to the skeleton
• Responsible for
voluntary movement
Nucleus
Width of one
muscle cell
Striation
7
Cardiac muscle• Branching striated cells,
one nucleus
• Involuntary contraction
• Found in wall of heart
• Pumps blood through
the body
Specialized
junction
Nucleus Striation
Smooth muscle• Cells tapered at each end,
one nucleus
• Involuntary contraction
• Found in walls of hollow
internal organs, such as
the intestines, and tubes,
such as blood vessels
• Contractions in digestive
system move food along
• When arranged in circle,
controls diameter of tube
Nucleus Smooth
muscle cell
Nervous Tissue
• Nervous tissue functions to conduct
messages throughout the body.
• Two types of nervous tissues cells
– Neurons
– Neuroglial (glial) cells
9
Organs & organ systems
• Organs are made up of two or more
different tissues functioning together towards a common purpose
• Organs that perform related functions are
grouped into organ systems.
• See page 73
Body cavities
The internal organs are suspended in body
cavities that protect the organs and allow organs to slide past one another as they
function and as the body moves.
10
Epithelial Membranes
1. Cutaneous membrane
2. Mucous membranes
3. Serous membranes
Connective Tissue Membranes
1. Synovial membranes
2. Meninges
Homeostasis
Definition:
Examples:
Homeostasis
• Homeostatic mechanisms do not maintain
absolute internal constancy, but they do dampen fluctuations around the variable’s
set point.
• The ability to maintain these variables within narrow limits is due to regulatory
control mechanisms.
11
Negative Feedback Loops
• Whenever a change occurs in a system,
the change activates a corrective mechanism which corrects the original
change.
• Receptor (sensor)
• Control center (integrator)
• Effector(s)
Homeostatic Control Systems
Positive feedback loops (parturition)
12
Integumentary System
Components of the Integumentary System
• Skin
• Nails
• Hair
• Sensory receptors
• Exocrine glands
Functions of the Integumentary System
1. Protection
2. Prevents excessive water loss
3. Temperature regulation
4. Vitamin formation
5. Keeps us informed about the outside
environment
13
Skin Layers
Epidermis – thin outer layer of keratinized stratified squamous epithelial cells
Epidermis
Skin Color
Skin color is based on the production of a
pigment called melanin by cells called melanocytes.
• Eumelanin
• Pheomelanin
Skin Color
1. Melanin
2. Hemoglobin
3. Carotene
3. Melanin
14
Functions of melanin
1. Skin & hair color
Albinism
2. Absorption of UV light
Dermis
Stretch marks (Striae)
16
Accessory structures – Sensory receptors Accessory structures - Nails
lakj
Accessory structures - Skin Glands
• Sudoriferous Glands
• Sebaceous Glands
First degree burns