Download Notes: Human Systems, Homeostasis and Feedback Inhibition

Notes: Human Systems,
Homeostasis and Feedback
Inhibition
EQ: How does the body regulate the
activities that allow it to live?
Human Systems
• Every cell in your body is both an independent
unit and an interdependent part of a larger
community (the entire organism)
Independent- not influenced or controlled by
others
Interdependent- to rely or depend on
something else
Human Systems
• The broadest levels of organization within
multicellular organisms are cells, tissues,
organ, and organ systems
Human Systems
• The eleven organ systems of the human body
work together to maintain homeostasis in the
body as a whole
– Integumentary (skin)
– Muscular
– Skeletal
– Respiratory
– Circulatory
—Reproductive
—Endocrine
—Excretory
—Digestive
—Nervous
—Lymphatic
Human Systems
• There are four types of tissue in the human
body:
1.
2.
3.
4.
Epithelial
Connective
Nervous
Muscle
1. Epithelial- Glands and tissues that cover
internal and external body surfaces
 Glands are structures that make and secrete a
particular product (ex. sweat, tears, hormones)
2. Connective- provide support for the
body and connects its parts
3. Nervous- transmits nerve impulses
throughout the body
4. Muscle- along with the bones,
enables a body to move
Homeostasis
• Homeostasis is the process where the body
keeps internal conditions relatively constant
despite changes in external conditions
Homeostasis
• A nonliving example of this is the heating
system of a house
– When the temperature drops below a set point
the thermostat turns the furnace on and then
when the temperature rises above the set point
the furnace turns off
– The furnace only runs when needed – this is an
example of feedback inhibition.
Feedback Inhibition
(Negative Feedback)
• Feedback inhibition (negative feedback) – a
process in which a stimulus produces a
response that opposes the original stimulus.
Feedback Inhibition
(negative feedback)
• Systems controlled by feedback inhibition are
generally fully automated and very stable.
• Feedback inhibition is what biological systems
(like the human body) use to achieve
homeostasis.
Feedback Inhibition
(negative feedback)
• The cellular environment
responds to feedback from its
own activities by switching on
and off as needed.
• The part of the brain that
works like a thermostat to
regulate and maintain a
stable body temperature is
the hypothalamus .
Feedback Inhibition
(negative feedback)
• The hypothalamus does this by sending
chemical messages that either speed up or
slow down cellular activity.
Positive feedback is a process in which the effects of a
small stimulus in a system includes an increase in the
magnitude of the stimulus.
Examples of positive feedback in the body are
blood clotting and childbirth.
What body systems is this rock
climber using?