1.1 - Intro to Cell Compounds

Question 1

What is an example of a single cell/unicellular organism?

Answer 1

euglena

Question 2

What 2 things do unicellular organisms, like euglena, need to survive?

Answer 2

1. Environment is a tolerable temp and composition 2. Able to obtain enough nutrients

Question 3

What do humans, made up of trillions of cells and extracellular fluid, need that unicellular organisms dont?

Answer 3

We need our internal environment to be kept relatively stable

Question 4

How does the human body maintain a relatively stable internal environment? and how much metabolic energy do we use to maintain it?

Answer 4

Homeostasis. The majority.

Question 5

How does the body maintain homeostasis?

Answer 5

Through many self regulating control systems aka homeostatic mechanisms

Question 6

What are the the 4 types of homeostatic mechanisms?

Answer 6

1. Change (Stimuli) 2. Receptor 3. Control centre 4. Effector

Question 7

How is change or stimuli defined within the homeostatic mechanism?

Answer 7

Anything that requires a cell to react

Question 8

What do receptors do within the homeostatic mechanisms?

Answer 8

Receptors detect change and alert the proper control centre

Question 9

What does a control centre do within the homeostatic mechanisms?

Answer 9

Firstly, It receives impulses from the receptor and compares it to a set point that a particular body factor should be (example body temp). Secondly it send a command to the effector to counteract the change

Question 10

What are effectors?

Answer 10

They are physical change agents that react to commands from the control centre to effect a change and return the body system to homeostasis

Question 11

What are examples of effectors?

Answer 11

muscles, glands, fluids in the body etc

Question 12

What are the 5 steps in a negative feedback loop?

Answer 12

1. Stimulus 2. Receptor detects change and sends message to the control centre 3. Control centre receives message from the receptor and send a command to the right effector 4. The effector creates a physical change that makes returns the body to normal conditions 5.Normal condition is achieved and cycle ends.

Question 13

What conditions in the body does negative feedback control for?

Answer 13

Body temp, CO2 levels, blood sugar levels, blood pH levels, osmoregulation, blood pressure etc

Question 14

What detects blood pressure in the arteries? What do they do when the sense bp out of the set point range?

Answer 14

Baroreceptors. They send a chemical signal to the control centre in the brain via the glassopharyngeal nerve.

Question 15

What does the brain do after recieving a chemical signal via the glassopharynheal nerve from the baroreceptors?

Answer 15

The send a command to the heart to adjust the rate of pumping; high blood pressure, heart slows. Low blood pressure, heart increases to increase blood output. Once the set point is reached the stimulus for increasing the heart rate decreases.

Question 16

Explain the 5 steps for the high body temp negative feedback loop.

Answer 16

1. Body is too hot 2. Nerve endings are stimulated and send a signal to the hypothalamus. 3. Hypothalamus sends a command to the sweat glands to sweat 4. Swear glands receive the command and sweat 5. Sweat cools the body, returning it to a normal temperature and ending the negative feedback loop

Question 17

Explain the 5 steps for the high CO2 negative feedback loop.

Answer 17

1. Body has a high level of CO2 2. Receptors are stimulated and send a signal to the medula oblongata 3. Medula oblongata sends a command to the an effector that causes breathing 4. Effector receives the command, breathes. 5. Breathing decreases the CO2 levels in the body and returns it to a normal level, ending the negative feedback

Question 18

What are the 5 general steps of a positive feedback loop?

Answer 18

1. Stimulus stimulates a receptor 2. Receptor sends a signal to the control centre 3. Control centre causes an adaptive response 4. Adaptive response triggers the control centre 5. This loop continues until the stimulus stops

Question 19

What is an example of a positive feedback loop?

Answer 19

Child birth: the head of the fetus into contact with the cervix causing a release of oxytocin that intensifies and speeds up contractions. Contractions cause more oxytocin to be released, cycle repeating until the baby is born.