Notes: Human Systems, Homeostasis and Feedback

InhibitionEQ: 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. Epithelial2. Connective3. Nervous4. 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?