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Human Body Systems Introduction
I.
Tasks of the body
A. Maintain homeostasis: stable operating conditions in the internal
environment, as brought about by coordinated activities of cells, tissues,
organs and organ systems
B. Acquire and distribute nutrients and dispose of waste
C. Afford protection against injury or attack
D. Reproduce then nourish and protect offspring in early development
II.
Levels of Organization
A. Cells  Tissues  Organs  Organ Systems
B. Tissue: groups of similar cells that perform a single function
C. Organ: group of tissues that work together to perform a complex function
D. Organ system: group of organs that perform closely related functions
E. The 11 systems of the body work together to maintain homeostasis
III.
Systems
Name
Structures
Function
Nervous
Brain, spinal cord, peripheral
nerves
Integumentary
Skin, hair, nails, sweat & oil
glands
Skeletal
Bones, cartilage, ligaments,
tendons
Muscular
Skeletal muscle, smooth
muscle; cardiac muscle
Circulatory
Heart, blood vessels, blood
Coordinates the body’s response to
changes in its internal and external
environments
Barrier against infection and injury;
helps regulate body temp; provides
protection against UV rays
Supports body; protects organs;
allows movement; store minerals;
produces red blood cells
Works with the skeletal system to
produce voluntary movement; helps
circulate blood and move food
through the digestive system
Brings O2, nutrients, and hormones
to cells; fights infections; regulates
body temp
Respiratory
Digestive
Excretory
Nose, pharynx, larynx, trachea, Provides O2 needed for cellular
bronchi, bronchioles, alveoli, respiration and removes excess
lungs
CO2 from the body
Converts
food into simpler molecules
Mouth, pharynx, esophagus,
that
can
be
used by cells of the body;
stomach, small intestine, large
absorbs food
intestine
Eliminates waste products of
Skin, lungs, kidneys, ureters,
metabolism
from the body; maintains
urinary bladder, urethra
homeostasis
Endocrine
Hypothalamus, pituitary,
thyroid, parathyroids, adrenals,
pancreas, ovaries, testes
Reproductive
Males: testes, epididymis, vas
Controls growth and
development, metabolism, and
reproduction with hormones
and steroids
Produces reproductive cells;
Lymphatic
deferens, urethra, and penis
Females: ovaries, Fallopian
tube, uterus, and vagina
White blood cells, thymus,
spleen, lymph nodes, lymph
vessels
nurtures and protects
developing embryos (in
females)
Helps protect the body from disease;
collects fluid lost from blood vessels
and returns the fluid to the
circulatory system
The immune system consists of many of these different systems.
IV.
Types of tissues
A. muscle tissue:
i.
most abundant tissue in body by mass
ii.
controls the internal movement of materials
iii. controls the external movements of the body
iv.
ex. heart
B. epithelial tissue:
i.
cells are closely packed
ii.
covers the surface of the body
iii. lines internal organs, ducts, and tubes
iv.
glands are made up from this type of tissue
v.
ex. lines heart chamber to prevent fluid leakage, skin
C. connective tissue:
i.
holds organs in place
ii.
binds different parts of the body together
iii. keeps organs flexible, but strong by secreting structural proteins
iv.
pads and insulates some body parts
v.
ex. tendons, ligaments, adipose tissue, blood, bone, and cartilage
D. nervous tissue
i.
receives messages from the body’s external and internal
environments, analyses the data, and directs the response
ii.
ex. nervous tissue in the heart controls the rate at which it beats
V.
Maintaining Homeostasis:
A. The cells of the body must be kept at a temperature within a specific range,
supplied with energy through cellular respiration, bathed in fluid, and
cleansed of their waste products.
B. Feedback Inhibition/Negative Feedback System
i.
Process by which the product of a system shuts down the system
or limits it operation
ii.
works like a thermostat
iii. ex. hypothalamus contains nerve cells that monitor the body’s
temperature from sensory receptors in the skin body core
1. if temp is low, the hypothalamus produces chemical signals that
speed up cell activity which produces heat
2. The hypothalamus detects increase in temp which will inhibit the
production of those chemicals which prevents temps from rising
to dangerous levels
C. Positive Feedback Mechanisms – chain of events that intensifies a change
from an original condition which eventually reverses the change; ex –
oxytocin during childbirth