Download Chapter 20 Unifying Concept of Animal Structure and Function

Chapter 20 Unifying Concept of
Animal Structure and Function
Microscopic hairs on the toes of a gecko
Structure and Function
in Animal Tissues
The structure hierarchy
in an animal begins with
cells and tissues, whose
forms correlate with their
functions.
Organs and
Organ Systems
Tissues are arranged into
organs, which may be
functionally correlated in
organ systems.
External Exchange and
Internal Regulation
Complex animals have internal
surface that facilitate exchange
with the environment.
Feedback control maintains
homeostasis in many animals.
Structure fits function at all levels of organization
in the animal body
Anatomy is the study of structure.
解剖學
Histology is the study of the microscopic anatomy of cells and tissues.
組織學
Physiology is the study of function.
生理學
Animals consist of a hierarchy of levels or organization.
組織
- Tissues are an integrated group of similar cells that perform a
common function.
器官
- Organs perform a specific task and consist of two or more tissues.
器官系統
- Organ systems consist of multiple organs that together perform a
vital body function.
The structure hierarchy in an animal
A. Cellular level
Muscle cell
B. Tissue level
Muscle tissue
C. Organ level
Heart Muscle tissue
D. Organ system level
Circulatory system
Nervous tissue
Epithelial tissue
Connective tissue
Heart
Blood
Blood vessels (arteries, veins, capillaries)
E. Organism level
Many organ systems
functioning together
An animal’s form reflects natural selection
 The body plan or design of an organism
- reflects the relationship between form and function.
- results from natural selection.
- does not imply a process of conscious invention.
 Streamlined and tapered bodies
- increase swimming speeds.
- have similarly evolved in fish, sharks, and aquatic birds
and mammals, representing convergent evolution. 趨同演化
Convergent evolution: the evolution of similar features in
different evolutionary lineages, which can result from living in
very similar environments.
Shark
Penguin
Seal
Convergent evolution of body shape in fast swimmers.
Tissues are groups of cells with a
common structure and function
組織 (weave)
Tissues are an integrated group of similar cells that
perform a common function and combine to form organs.
 Animals have four main categories of tissues:
上皮組織 (1) epithelial tissue.
結締組織 (2) connective tissue.
肌肉組織 (3) muscle tissue.
神經組織 (4) nervous tissue.
Epithelial tissue covers the body and
lines its organs and cavities
Epithelial tissues, or epithelia, are sheets of closely packed cells
- cover body surfaces.
- line internal organs and cavities.
Epithelial tissues are named according to the
(1) number of cell layers they have.
- simple epithelium 單層上皮組織
- stratified epithelium 複層上皮組織
- pseudostratified epithelium 偽複層上皮組織
(2) shape of the cells on their apical surface.
- squamous 鱗狀(扁平)上皮
- cuboidal 立方上皮
- columnar 柱狀上皮
基底層
Types of epithelial tissue
Apical surface of
epithelium
Basal lamina
(extracellular matrix)
Underlying
tissue
Cell nuclei
A. Simple squamous epithelium
E. Pseudostratified ciliated
columnar epithelium
(capillaries, air sacs of the lung)
(lining the respiratory track)
B. Simple cuboidal epithelium
(thyroid gland, salivary gland, tube in the kidney)
D. Stratified squamous epithelium
(lining the esophagus and mouth)
C. Simple columnar epithelium
(lining in the intestine)
Connective tissue binds and supports other tissues
Connective tissues consists of a sparse population of cells scattered
throughout an extracellular material called a matrix.基質
The cells produce and secrete the matrix.
Connective tissue can be grouped into six major types:
(1) Loose connective tissue 疏鬆性結締組織.
- is the most widespread.
- consists of ropelike collagen and elastic fibers that are strong and resilient.
- mainly to bind epithelia to underlying tissues and hold organs in place.
(2) Fibrous connective tissue 纖維(緻密)結締組織
- has densely packed collagen fibers.
- forms tendons that attach muscle to bone; ligaments connect bones at joints.
(3) Adipose tissue 脂肪組織
- stores fat in large, closely packed adipose cells held in a matrix of fibers.
- this tissue pads and insulates your body and store energy.
(4) Cartilage 軟骨組織
- is a strong and flexible skeletal material.
- Consists of collagen fibers embedded in a rubbery material.
- commonly surrounds the ends of bones.
(5) Bone 骨組織
- has a matrix of collagen fibers.
- embedded in a hard mineral substance containing calcium,
magnesium, and phosphate.
(6) Blood 血液組織
- transports substances throughout the body.
- its extensive ECM (extracellular matrix) is liquid called plasma.
Types of connective tissue
White blood
cells
Red blood
cell
Central
canal
Plasma
Cell
nucleus
Collagen
fiber
Elastic
fibers
Matrix
F. Blood
E. Bone
A. Loose connective tissue
(under the skin)
Cell nucleus
Collagen
fibers
Fat
droplets
adipose cells
B. Fibrous connective tissue
C. Adipose tissue
(forming a tendon, ligament)
Boneforming
cells
Cartilageforming
cells
Matrix
D. Cartilage
(at the end of a bone, ear, nose
cushioning disks between vertebrate)
Muscle tissue functions in movement
Muscle tissue is the most abundant tissue in most animals.
There are three types of vertebrate muscle tissue:
骨骼肌 - Skeletal muscle causes voluntary movements.
心肌 - Cardiac muscle pumps blood.
平滑肌 - Smooth muscle moves walls of internal organs,
such as the intestines.
Muscle
fiber
Unit of
muscle
contraction
Muscle fiber
(cell)
Nuclei
Junction between
two cells
Nucleus
B. Cardiac muscle
Muscle fiber Nucleus
A. Skeletal muscle
C. Smooth muscle
Skeletal muscle
Cardiac muscle
Smooth muscle
Striped/Striated
Yes
Yes
No
Nucleus location
Peripheral
Central
Central
Nucleus number
Multiple
Single
Single
Branched
No
Yes
No
Voluntary movement
Yes
No
No
Contraction speed
Fast
-
Slow
Contraction time
Short
-
Long
Nervous tissue forms a communication network
 Nervous tissue
- senses stimuli.
- rapidly transmits information.
神經元
 Neurons carry signals by
conducting electrical impulses.
樹突 Dendrites
細胞本體
Cell body
軸突
Axon
神經膠細胞
 Other cells (glial cell) in nervous tissue
- insulate axons.
- nourish neurons.
- regulate the fluid around neurons.
Organs are made up of tissues
 Each tissue performs specific functions.
 The small intestine
- is lined by a columnar epithelium
that secrete digestive juices and
absorbs nutrients.
Lumen
- the inner surface of the
Epithelial tissue
small intestine has many
(columnar epithelium)
fingerlike projections that
increase the surface area
Connective tissue
for absorption.
- includes connective tissues
that contain blood vessels.
Smooth muscle
- has two layers of smooth muscle tissue (two layers)
that help propel food.
Connective tissue
Epithelial tissue
Small intestine
Bioengineers are learning to produce tissues and organs
for transplants
生物工程
 Bioengineering is seeking ways to repair or replace damaged
tissues and organs.
 New tissues and organs are being grown using a patient’s own cells.
 These techniques
- remove the risk of tissue rejection.
- may reduce the shortage of organs available for transplants.
A laboratory-grown bladder
Artificial skin
Artificial skin
Human skin
Organ systems work together to perform life’s functions
Each organ system typically consists of many organs,
has one or more functions, and works with other organ systems
to create a functional organism.
循環系統
A. Circulatory
system
呼吸系統
B. Respiratory
system
Nasal
cavity
Heart
Pharynx
Larynx
Trachea
Bronchus
Lung
Blood
vessels
Exchanges gases
O2 in
CO2 out
O2, nutrients body cells
CO2 lungs
Metabolic wastes  kidneys
體被系統
C. Integumentary system
骨骼系統
D. Skeletal system
Hair
Skin
Bone
Nails
Cartilage
Against
- physical injury
- infection
- excessive heat or cold
- drying out
Supports body
Protects organs
Provides the frameworks for muscle
E. Muscular system 肌肉系統
Moves body
Maintains posture
Produces heat
泌尿系統
F. Urinary system
Skeletal muscles
G. Digestive system 消化系統
Mouth
Remove waste products from blood
Ingests & digests food
Excretes urine
Esophagus Absorbs nutrients
Liver Eliminates undigested
material
Kidney
Stomach
Small
Ureter
intestine
Urinary
Large
bladder
intestine
Urethra
Anus
Returns excess body fluid  circulation system
Part of the immune system
I. Lymphatic system
淋巴系統
H. Endocrine system
內分泌系統
Hypothalamus
Pituitary gland
Thymus
Adrenal
gland
Pancreas
Testis
(male)
Lymph
Thyroid gland nodes
Parathyroid
gland
Appendix
Ovary
(female)
Secrete hormones
To maintain homeostasis
Bone
marrow
Thymus
Spleen
Lymphatic
vessels
免疫系統
J. Immune system
Against infection & cancer
神經系統
K. Nervous system
Brain
Sense organ
(ear)
Spinal cord
Nerves
Detecting stimuli

Integrating information

Directing the body’s responses
L. Reproductive system
生殖系統
Supports a developing embryo
Products milk
Seminal
vesicles
Female
Male
Oviduct
Prostate
gland
Ovary
Vas
deferens
Uterus
Penis
Vagina
Testis
Produces gametes and sex hormones
Urethra
New imaging technology reveals the inner body
New technologies
- are used in medical diagnosis and research.
- allow physicians to examine organ systems without surgery.
(1) X-rays
X光照射
(2) CT: computed tomography
電腦斷層掃描
(3) MRI: magnetic resonance imaging
核磁共振造影
(4) PET: positron-emission tomography
正子斷層顯影術
(1) X-rays
X-rays
- high-energy radiation.
- passes readily through soft tissues.
- shadows of hard structures (bone, teeth, dense tumors).
(2) CT: computed tommography
 A newer X-ray technology called computed tomography (CT).
- produces high-resolution images of a series of thin cross section
of the body.
- can detect small differences between normal and abnormal tissues
in many organs (abdomen, brain).
(3) MRI: magnetic resonance imaging
Magnetic resonance imaging (MRI)
- takes advantage of the behavior of the
hydrogen atoms in water molecules.
- visualize soft tissues well.
(water is the major component of soft tissues)
- provides three-dimensional images of
very small structures.
Femur
(thigh bone)
Torn meniscus
Tibia (shin bone)
(4) PET: positron-emission tomography
 PET helps identify metabolic processes at specific body locations.
 The patient is injected with a small amount of
radioactive isotope labeled molecule (glucose).
Examples of PET
CT and PET images can be combined for an
even more informative image
CT: better anatomical representation.
PET: metabolic information.
A combined CT-PET scan showing tumors (bright white)
in the upper left lung and lower abdomen
The integumentary system protects the body
(skin, hair and nails)
 The skin consists of two layers:
1. The epidermis 表皮
- is a stratified squamous epithelium.
- forms the surface of the skin.
2. The dermis 真皮
- forms a deeper skin layer and
- is composed of dense connective tissue with
many resilient elastic fibers and strong collagen fibers.
- the dermis contains hair follicles, oil and sweat glands,
muscle cells, nerves, sensory receptors, and blood vessels.
A section of skin, the major organ
of the integumentary system
Hair
Epidermis
Sweat
pore
Muscle
Dermis
Nerve
Sweat
gland
Hypodermis
(under the skin)
Adipose tissue
Blood vessels
Oil gland
Hair follicle
Sensory receptors in the human skin
Heat
Light touch
Pain
Cold
Hair
Epidermis
Dermis
Nerve
to brain
Connective
tissue
Hair
movement
Strong
pressure
 Skin has many functions.
- The epidermis resists physical damage, decreases water loss,
and prevents penetration by microbes.
- The dermis collects sensory information, synthesizes vitamin D,
and helps regulate body temperature.
 Exposure of the skin to ultraviolet light.
- causes skin cells to release melanin, which contributes to a
visible tan.
- damages DNA of skin cells and can lead to
a. premature aging of the skin.
b. cataracts.
c. skin cancers.
Hair and Nails
 Hair
- produced by a hair follicle.
- helps to insulate their bodies.
- consists of a shaft of flattened
keratin-filled dead cells.
油脂腺
 Oil glands release oils that
- are associated with hair follicles.
- lubricate hair.
- condition surrounding skin.
- inhibit the growth of bacteria.
 Fingernails and toenails
- composed of keratin.
- protective coverings.
- facilitates fine manipulation.
Structural adaptations enhance exchange
with the environment
 Every organism is an open system that must exchange matter
and energy with its surroundings.
 Cells in small and flat animals can exchange materials directly
with the environment.
Hydra
 Organisms increase in size, the surface area
- is too small for the corresponding volume.
- too far away from the deepest cells of the body.
 In these organisms, evolutionary adaptations
- consist of extensively branched or folded surfaces, which increase
the area of these surfaces.
- provide for sufficient environmental exchange.
Indirect exchange between the environment and the cells
EXTERNAL ENVIRONMENT
CO2 O
Food
2
Mouth
of a complex animal
Digestive
system
Blo
o
ANIMAL
d
Respiratory
system
Interstitial
fluid
Heart
Nutrients
Circulatory
system
Body
cells
Urinary
system
Intestine
Anus
Unabsorbed
matter (feces)
Metabolic waste
products (urine)
Interstitial fluid:
An aqueous solution that surrounds
body cells and through which
materials pass back and forth
between the blood and the body tissues.
Trachea
A resin model of the finely branched air tubes (white)
and blood vessels (red) of the human lungs
Animals reguate their internal nvironment
Two environments:
- external environment
- internal environment
the interstitial fluid that fills the spaces around the cells.
Claude Bernard
The father of Physiology
不變的; 變動性很少的; 靜恆狀態的
Homeostasis is the active maintenance of a steady state
within the body.
- external environmental conditions
may fluctuate wildly.
- homeostatic mechanisms
regulate internal conditions.
恆定
External
environment
Homeostatic
mechanisms
Large
fluctuations
Internal
environment
Small
fluctuations
A model of homeostasis in a white-tailed ptarmigan in its snowy habitat
Homeostasis depends on negative feedback
Control systems
- detect change.
- direct responses.
負回饋
Negative-feedback mechanisms
- keep internal variables steady.
- permit only small fluctuations around set points.
Negative feedback is a common control mechanism in which a
chemical reaction, metabolic pathway, or hormone-secreting gland
is inhibited by the products of the reaction, pathway, or gland.
Sweat evaporates,
cooling the body.
Brain activates
cooling
mechanisms.
Blood vessels dilate.
Temperature
decreases
Cooling mechanisms
shut off.
Temperature rises
above set point
Homeostasis:
Body temperature
approximately 37°C
Temperature
increases
Warming mechanisms
shut off.
Temperature falls
below set point
Blood vessels constrict.
Brain
activates
warming
mechanisms.
Shivering generates
heat.
Feedback control of body temperature