Transcript Animal Tissues and Organ Systems

Animal Tissues and Organ
Systems
Chapter 20
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
Epithelial Tissues
• Line body surfaces, cavities, ducts, and
tubes
• One free surface faces a body fluid or the
environment
basement
membrane
simple
squamous
epithelium
connective tissue
free surface of
epithelium
Epithelium
simple epithelium
basement membrane
connective tissue
Glands
• Secretory organs derived from
epithelium
• Exocrine glands have ducts or tubes
• Endocrine glands are ductless
Cell Junctions
• Tight junctions
prevent leaks
• Gap junctions
connect abutting
cytoplasms
• Adhering junctions
cement cells together
Tight
junctions
Adhering
junction
Gap
junctions
Connective Tissues
• Most abundant tissues in the body
• Fibroblasts secrete
– polysaccharide “ground substance” that
surrounds and supports cells
– fibers of collagen and/or elastin
Soft Connective Tissues
• Loose connective tissue
• Dense, irregular connective tissue
• Dense, regular connective tissue
Specialized Connective Tissues
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Cartilage
Bone tissue
Adipose tissue
Blood
white blood cell
platelet
red blood cell
cells and platelets of
blood
Fig. 20-3g, p.342
Muscle Tissue
• Cells contract when stimulated
• Moves body and specific body parts
• 3 types
– Skeletal
– Cardiac
– Smooth
Skeletal Muscle
• Attaches to and moves
bones
• Long, cylindrical cells
• Striated cells
• Voluntary control
nucleus
Smooth Muscle
• Located in soft internal
organs and blood vessels
• Cells taper at ends
• Cells not striated
• Not under voluntary control
where abutting cells meet
Cardiac Muscle
• Present only in heart
• Cells are branching
– ends of cells joined by communication
junctions
• Cells striated
• Not under voluntary control
cell nucleus
Nervous Tissue
• Detects stimuli, integrates information,
and relays commands for response
• Consists of excitable neurons and
supporting neuroglial cells
Neurons
Functional zones of a motor neuron
Neurons
• Excitable cells
• Stimulus sends electrical impulse along
plasma membrane
• Transmits information to other neurons,
muscles or glands
Neuroglia
• Neuroglial cells make up more than half of
nervous tissue
• Protect and support neurons
11 Major Organ Systems
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Integumentary
Nervous
Muscular
Skeletal
Circulatory
Endocrine
Lymphatic
• Respiratory
• Digestive
• Urinary
• Reproductive
11 Major Organ Systems
Integumentary
System
Nervous
System
Muscular System
Skeletal
System
Circulatory
System
Endocrine
System
Fig. 20-6, p.344a1
11 Major Organ Systems
Lymphatic
System
Respiratory
System
Digestive
System
Urinary
System
Reproductive
System
Fig. 20-6a2, p.344
Position References:
Animals
dorsal surface
anterior
midsagittal plane
posterior
transverse plane
frontal plane
ventral surface
Fig. 20-6b, p.345
Position References: Humans
frontal plane
(aqua)
transverse plane
(yellow)
midsagittal plane (green)
Major Body Cavities
• Cranial cavity
• Spinal cavity
• Thoracic cavity
• Abdominal cavity
• Pelvic cavity
cranial
cavity
spinal
cavity
thoracic
cavity
abdominal
cavity
pelvic
cavity
Fig. 20-6d, p.345
Primary Tissues
• Three primary tissues in vertebrate embryos
give rise to all adult tissues:
Ectoderm
Mesoderm
Endoderm
Skin: An Organ System
• Epidermis: Stratified
epithelium
• Dermis: Dense
connective tissues
• Hypodermis: Loose
connective tissue and
adipose tissue
hair
epidermis
dermis
sensory
neuron
hypodermis
(below skin,
not part of it)
sweat gland
oil gland
hair follicle
blood vessels
smooth muscle
Fig. 20-7a, p.346
outermost
epidermal
layer (all
dead cells)
keratinized
cells being
flattened
rapidly
dividing
cells of
epidermis
dermis
Fig. 20-7b, p.346
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
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
Langerhans Cells
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White blood cells in skin
Attack viruses and bacteria
Stimulate immune system
Are damaged by UV exposure
Epithelial Tissues