ch. 28 notes: human systems and homeostasis. objectives 10c analyze the levels of organization in...
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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.