Download Chapter 20: Tissues & Organ Systems The Importance of Homeostasis

Chapter 20:
Tissues & Organ Systems
The Importance of Homeostasis
The maintenance of a relatively constant
internal environment, i.e., homeostasis, is
essential for life.
Cellular conditions that need to be maintained
within a narrow range include:
Temperature
pH
concentrations of: minerals, nutrients, wastes
Negative Feedback
Homeostasis is largely maintained by what is
known as Negative Feedback:
• counteracting a change in body state to
restore the original state
e.g.
• sweating to cool an overheated body
• releasing insulin to lower blood sugar
• accelerated breathing, pulse to increase oxygen
**various sensory systems in the body detect
changes and trigger negative feedback responses**
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Organization of the Animal Body
A
B
CELLULAR LEVEL
Muscle cell
TISSUE LEVEL
Muscle tissue
C
D
ORGAN LEVEL
Heart
ORGAN SYSTEM LEVEL
Circulatory system
E
ORGANISM LEVEL
Many organ systems
functioning together
The 4 Basic Tissue Types
All tissues in the animal body fall into one of
4 basic tissue types:
Epithelial Tissue
Connective Tissue
Muscle Tissue
Nerve Tissue
Epithelial Tissue
Sheets of cells that line
body surfaces, cavities:
skin; digestive, urinary,
reproductive tracts;
vessels; glands
Epithelial cells come in
3 basic shapes…
• squamos (flattened)
• cuboidal (cube-shaped)
• columnar (elongated)
…and in single or
multiple layers:
simple or stratified epith.
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Examples of Epithelial Tissue
simple squamous
epithelium (lung)
stratified squamous epithelium
(lining the esophagus)
simple cuboidal
epithelium (kidney)
Colorized SEM
dead cells
rapidly
dividing
cells
stratified squamous epithelium
simple columnar epithelium (intestine)
(human skin)
Connective Tissue
Tissue that supports, binds, “fills” or provides
structure.
• contains few cells, mostly extracellular matrix (ECM)
Connective Tissue (CT) comes in 3 basic types:
Loose CT – underlies epithelium, loosely woven fibers,
“gel-like”
Fibrous or Dense CT – densely packed fibers as in
tendons & ligaments
Specialized CT – bone, cartilage, blood & lymph,
adipose (fat) tissue
Examples of Connective Tissue
Fat
droplets
Cartilageforming
cells
adipose tissue
Matrix
Cell
nucleus
cartilage (end of a bone)
Collagen
fibers
Central
canal
fibrous connective
tissue (tendon)
White blood
cells
Matrix
Red blood
cell
Boneforming
cells
bone
Plasma
loose connective tissue
(under the skin)
blood
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Muscle Tissue
Made of cells that contract, comes in 3 types:
Skeletal Muscle (striated, voluntary – moves skeleton)
Cardiac Muscle (striated, involuntary – heartbeat)
Smooth Muscle (unstriated, involuntary – visceral org., vessels)
Muscle
fiber
Unit of
muscle
contraction
Muscle
fiber
Junction between
two cells
Nucleus
Nucleus
Muscle fiber
Nucleus
cardiac muscle
skeletal muscle
smooth muscle
Nerve Tissue
Tissue that transmits electrochemical signals.
neuron
Contains 2 basic cell types:
Cell body
Neurons – cells that generate,
transmit electrical signals
Nucleus
Glial cells (glia) – metabolic
support, insulation for neurons
Organs and Organ Systems
Organs = multiple tissues that comprise a
physically & functionally distinct structure
Organ systems = multiple organs that work
together to perform a common function
• each tissue and organ has a distinct role
e.g. – Integumentary System (skin, nails, etc)
• skin, nails, hair each have different roles
• each contains multiple tissues (epithelium,
connective tissue, muscle, nerve) with diff. roles
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Organs are made of all Tissue Types
Small intestine
(cut open)
Lumen
Lumen
epithelial tissue
(columnar epithelium)
connective tissue
smooth muscle
tissue (2 layers)
connective tissue
epithelial tissue
The 11 Major Organ Systems
Endocrine
System
hypothalamus
Skeletal
System
bone
adrenal
gland
ovary (female)
(endocrine glands)
• hormone production
pituitary gland
thyroid gland
parathyroid
gland
Endocrine System
• physiological control
cartilage
Skeletal System
pancreas
testis
(male)
(bones, cartilage…)
• structural support
• blood production
• calcium, phosphorus
storage
Organ Systems cont’d…
Circulatory System
(blood & vessels, heart)
Circulatory
System
• transport of nutrients,
wastes, cells, hormones
• temperature control
heart
Respiratory System
nasal cavity
larynx
trachea
bronchus
lung
• pH balance
Respiratory System
blood
vessels
(pharynx, trachea, lungs)
• gas exchange
• pH balance
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Organ Systems cont’d…
Muscular System
Muscular
system
(all 3 muscle types)
• movement of skeleton
Integumentary
system
skeletal
muscles
• movement in the
hollow organs
• heartbeat
hair
nails
Integumentary
System (skin, hair…)
skin
• protection from external
threats
• temperature balance
Organ Systems cont’d…
Digestive System
Urinary
system
(esophagus, stomach,
liver, intestines,
pancreas)
• digestion, absorption
of food
• waste disposal
mouth
kidney
esophagus
ureter
liver
stomach
small
intestine
urinary
bladder
urethra
Urinary System
Digestive
system
large
intestine
(kidneys, bladder)
• blood-borne waste
disposal
anus
• salt & water
homeostasis
brain
Nervous System
sense organ
(brain, spinal cord, nerves)
spinal
cord
Nervous
system
• internal, external sensation
• behavioral control
• physiological control
nerves
Reproductive
Systems
Female
oviduct
ovary
uterus
vagina
Male
seminal
vesicles
prostate
vas deferens
penis
urethra
testis
Reproductive Systems
(ovaries, uterus, testes…)
• gamete, production
• hormone production
• nurturing offspring
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Organ Systems cont’d…
Lymphatic and Immune Systems
thymus
Lymphatic & Immune
Systems
(lymph, lymphatic vessels,
lymph nodes, thymus,
spleen, white blood cells)
• fluid balance, transport
bone
marrow
spleen
lymph nodes
lymphatic
vessels
• fat transport
• immune responses
Key Terms for Chapter 20
• homeostasis
• epithelium – squamous, cuboidal, columnar
simple & stratified
• connective tissue – loose, fibrous, specialized
• skeletal, smooth & cardiac muscle
• neurons & glial cells
Relevant Review Questions:
2-14
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