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: 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?