Ch. 28 Notes: Human Systems and Homeostasis. Objectives 10C analyze the levels of organization in biological systems and relate the levels to each other.

Ch. 28 Notes: Human Systems and Homeostasis

Objectives

10C analyze the levels of organization in biological systems and relate the levels to each other and to the whole system

4B investigate and explain cellular processes, including homeostasis, energy conversions, transport of molecules, and synthesis of new molecules;

Objectives

10A describe the interactions that occur among systems that perform the functions of regulation, nutrient absorption, reproduction, and defense from injury or illness in animals;

11A describe the role of internal feedback mechanisms in the maintenance of homeostasis

Cell differentiation Specialized cells in multicellular organisms

arise from a single cell, the zygote (sperm + egg)

Cell differentiate into hundreds of different types of cells Cell differentiation- process by which cells become specialized and develop into their mature form and function. Bone cells, smooth muscle cells, skin cells, sperm cells, nerve cells- all different!

Levels of organization Contain 5 levels

Cells- preform a specific task Ex- epithelial lung cell

Tissues- groups of similar cells working together to perform a function Ex- epithelial lung tissue

red blood cell nerve cell tissue

Organs- A group of tissues that carry out a special function Ex- lungs

Organ systems- Two or more organs the work together to preform body functions Ex- respiratory system

Organism- all the combined organ systems. Must work together to stay alive Ex- human being

ORGANS

ORGAN SYSTEM

ORGANISM

Mechanisms of Homeostasis Conditions in the body must remain within

a narrow range Homeostasis- the regulation and

maintenance of a stable internal environment Ex- sweating when you’re hot

Can you think of another example of homeostasis in the body?

_________________ is an example of homeostasis in the body because _________________________

28.2 Mechanisms of Homeostasis TEKS 4B, 10A, 11A

• Control systems help maintain homeostasis.

–sensors gather data–control center receives

data, sends messages –communication system

delivers messages to target organs, tissues

– targets respond to change

pore

sweat glands

hairfolliclemuscle

goosebump

Feedback Loops are used by your body to maintain homeostasis Negative feedback- a control system receives a stimulus and tries to counteract the change. Ex- a thermostat. When it gets hot (the stimulus), the AC starts to blow cold air (tries to counteract the change)

Holding breath, CO2 levels rise,

Control system forces exhale, inhale

O2 / CO2 level returns to normal

Positive feedback- a control system receive a stimulus and tries to promote the change Ex- think snowball effect

platelets

fibrin

white blood cellred blood cell

blood vessel

clot

Systems interact to maintain homeostasis Each organ system affects other organ systems Thermoregulation- process where the body regulates

it internal temperature Uses skin (integumentary system), muscles

(muscular system), nervous system, circulatory, respiratory and endocrine systems.

Sweating: Sensors in the skin provide information to the nervous system (brain and hypothalamus), which sends chemical messengers through the endocrine system to the circulatory and integumentary systems

Also works when you shiver when cold

Disruption of homeostasis can be harmful Short term effects- last for a few days or

weeks- Ex: getting a cold Long term effects- last much longer- Ex:

diabetes- cannot regulate amount of glucose in blood More serious than short term effects.