BODY SYSTEMS
General
 Anatomy
 Study of an organism’s structure – parts that
compose it and their location in the body
 Physiology
 Describes how those parts work
 Organizational hierarchy in the body
 Cells
 Tissues – groups of cells (two or more different cells)
that interact and provide specific functions
 Organs – made of 2 or more different interacting
tissues
 Organ systems – 2 or more organs joined physically
or functionally
Hierarchy
Tissues
 A tissue is a group of two or more different cells that work
together to perform a common task or specific function.
 Stem cells are cells that are not specialized (less
differentiated) but give rise to cells that can differentiate
 4 basic types of animal tissues:
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•
•
•
Epithelial
Connective
Nervous
Muscle
Epithelial Tissue
 Consists of one or more layers of tightly packed cells;
deepest layer is anchored to a basement membrane.
• covers body surfaces
• lines hollow organs & body cavities
• lacks blood vessels (avascular)
• functions in protection, absorption & secretion
Epithelial Tissues are classified by:
• Shape of cells on the surface
• Number of layers
Derived structure include hair, scales, feathers, and glands
Epithelial Tissue
Connective Tissue
 Consists of widely spaced cells embedded in a non-living
extracellular matrix.
• most possess blood vessels (vascular)
• functions are highly diverse
 Connective tissues are classified by matrix composition,
types of fibers, cell specializations, and ratio of cells to
matrix.
 Types:
 Loose Connective
 Dense Connective
 Adipose (fat)
 Blood
 Cartilage
 Bone
Connective Tissue
Muscle Tissue
 Consists of contractile cells.
• provides voluntary &
involuntary movements
• contracts when actin &
myosin filaments slide past
each other. (Myosin changes
shape)
• protein interaction.
Three types:
 Skeletal
 Cardiac
 Smooth
Nervous Tissue
 Consists of neurons (nerve
cells) and neuroglia (support
cells).
 Typical neuron has dendrites,
cell body & axon.
 Neurons function to transmit
signals from one part of the
body to another.
 Communication
Organ Systems of Humans
 11 different organ systems
 Organ is composed of two or more different tissues that
work together to perform a common task or function
 Organs system is composed of two or more organs that
work together to perform a common task or function.
 Function to of all 11 systems is to maintain homeostasis.
5 groups of organ systems
1.
Communication
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–
2.
Nervous system
Endocrine system
Support and movement
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–
3.
Skeletal system
Muscular system
Acquiring energy
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–
–
4.
Digestive system
Cardiovascular system
Respiratory system
Protection
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–
–
5.
Integumentary system
Urinary system
Immune system (Lymphatic system)
Reproduction
–
Reproductive system
Communication
1. Nervous System (Brain, spinal cord and Nerves)
 Detects, interprets & responds to stimuli from outside & within body.
 Rapid communication.
2. Endocrine System (Endocrine Glands and Hormones)
 Secretes hormones that travel in the bloodstream.
 Hormonal communication – slow communication with target but
prolonged effects.
Nervous & endocrine systems integrate & coordinate activities
of all organ systems.
Support and Movement
3. Skeletal System (Skeleton)
 Provides framework for muscle attachment; contains bone
marrow; protects soft organs; stores minerals.
4. Muscular System (Muscles)
 Enables body to move; provides for heartbeat, digestion & lung
function.
Skeletal & muscular systems interact to provide support
and allow movements.
Acquiring Energy
5. Respiratory System (Lungs and passageways)
 Gas exchange - obtains O2 & releases CO2.
6. Cardiovascular System (Heart, Vessels, and Blood)
 Transports O2, CO2, nutrients, hormones & metabolic wastes.
7. Digestive System (Stomach, Intestines, Liver, and Pancreas)
 Breaks down nutrients & eliminates undigested food.
These 3 systems interact to provide us with energy (ATP)
and energy transport.
Protection
8. Integumentary System (Skin and Glands)
 Serves as a barrier; helps regulate body temperature; conserves
water.
9. Urinary System (Kidneys, Bladder, and Passageways)
 Excretes metabolic wastes and toxins; maintains volume &
composition of body fluids.
10. Immune System (Lymph nodes, Vessels, and Lymph)
 Protects body from infection, injury & cancer.
These 3 systems protect the body.
Reproduction
11. Reproductive System (Gonads and Genitalia)
 Enables an individual to produce gametes, gamete transfer, and
the female to carry & give birth of offspring.
 Gametes are sperm and ova
The reproductive system is vital for perpetuation of the
species.
Homeostasis
 Internal environment of
interstitial fluid and plasma
must be kept constant
 External environment
changes constantly
 Homeostasis – maintaining
a state of internal
constancy
 Tissues and organs work
together to maintain
homeostasis
Feedback loops
 Negative feedback
 Most common
 Action counters an existing
condition
 Sensors monitor variable
 Effector’s response
counteracts change
 Positive feedback
 Less common
 Amplifies change
 Blood clotting
 Milk secretion
Overview