Lecture 2: Homeostasis (and Cells)

Question 1

what is homeostasis?

Answer 1

homeo-sameness
stasis-standing

is the body remaining a relatively constant internal environment by the function of cells, tissues and organs, despite a constantly changing external and internal environment

Question 2

why is homeostasis important?

Answer 2

-maintains life of the body
-important in understanding both normal function and certain disabilities and disease
-core concept of physiology

Question 3

homeostasis is a constant process of cause and effect, it is not true that……but rather

Answer 3

it is not true that the body wants what is best for itself,, it is true that homeostatic regulation occurs regardless of what may be best

Question 4

what is an example of how homeostatic regulation occurs regardless of what is best?

Answer 4

blood pressure regulation and hemmorhage

-major blood loss –> decreased bp –> bp regulated by homeostasis –> faster blood loss

Question 5

there are homeostatic regulated variables called…

Answer 5

the big 10

dont need to memorize but a lot to do with blood

Question 6

it is not true that non-homeostatic regulated variables aren’t important, but rather…

Answer 6

other variables have their own functions and help support homeostasis

Question 7

how does the body regulate the big 10?

Answer 7

1. via the nervous system and/or endocrine system
2. through a process called a feedback loop

Question 8

what are the different parts of the feedback loop in order?

Answer 8

1. stimulus (anything that causes change)
2. controlled variable/system (one of the big 10)
3. sensor (type of receptor)
   4a. integrator (brain or endocrine organ)
   4b. set point
4. effectors (cell, tissue, organ)
5. response (physiological change)

Question 9

know the feedback loop like the back of your hand

Answer 9

;)

Question 10

what are the two types of feedback loops?

Answer 10

1. positive feedback
2. negative feedback

Question 11

what is a positive feedback loop?

Answer 11

when the response is in the same direction as the stimulus

pro change

ex. childbirth and contractions,, baby begins to come out, so the body pushes harder to get it out

Question 12

what is a negative feedback loop?

Answer 12

when the response is in the opposite direction of the stimulis

Question 13

homeostasis uses_______ feedback loops only

Answer 13

negative

Question 14

look at the cruise control as a negative feedback example

Answer 14

;)

Question 15

homeostatic feedback is like a ________ not a _________

Answer 15

volume knob

light switch

Question 16

go look at the blood osmo. and blood glucose feedback examples

Answer 16

;)

Question 17

the cytoplasm

Answer 17

a combination of the cytosol and the organelles

Question 18

what is the cytosol?

Answer 18

a jelly like substance that provides a fluid like medium for chemical reactions within the cytoplasm

Question 19

what are organelles?

Answer 19

tiny organs

Question 20

what is the nucleus?

Answer 20

-the central organelle
-contains DNA
-contains nucleolus
-contains chromatin

Question 21

what is the nucleolus?

Answer 21

a structure within the nucleus with specific functions

Question 22

what is the chromatin?

Answer 22

a complex combination of DNA and protein

Question 23

endoplasmic reticulum?

Answer 23

a system of passages with the nucleus that allow for synthesis transport, and storage of cellular materials

2 forms (rough and smooth)

Question 24

rough ER

Answer 24

-ER covered in ribosomes giving it a rough appearance
-important in protein synthesis

Question 25

smooth ER

Answer 25

-involved in lipid synthesis and detoxification of foreign substances (drugs)

Question 26

golgi apparatus

Answer 26

the “post-office” of the cell

-sorts, modifies, and transports products from the rough and smooth ER’s

-products are transported through Golgi vesicles

Question 27

vesicles

Answer 27

-liquid or cytoplasm enclosed by a phospholipid bylayer used for transport purposes

Question 28

vesicular transport is used when…

Answer 28

1. large substances need to be moved across the plasma membrane
2. large quantities of substances need to be moved quickly

Question 29

what are the two types of vesicular transport?

Answer 29

1. exocytosis: moves substances OUT of the cell
2. endocytosis: brings substances INTO the cell

Question 30

what are the lysosomes

Answer 30

-the “garbage trucks” of the cell
-contain hydrolytic enzymes
-also break down old cellular structures and foreign substances, and can cause the cell to self destruct if needed
-generated by the golgi

Question 31

mitochondria

Answer 31

-plural-mitochondrion
-synthesizes ATP through cellular respiration and is the site of major metabolic reactions
-some cells have more ATP than others

Question 32

why would some cells have more ATP than others?

Answer 32

some cell types need to process more energy than others ie. muscle cells

Question 33

what are peroxisomes?

Answer 33

-similar to lysosomes but contain digestive enzymes
-have some metabolic functions, make lipids and cholesterol

Question 34

the cytoskeleton

Answer 34

-groups of proteins that provide structural support for the cell
-supports cell motility, cell reproduction, and transportation of substances within the cell
-microtubules, microfilaments (actin) and centrosomes