animal physiology - challenge 2 (Intracellular Communication)

Question 1

because animals are multicellular this proposes what challenge?

Answer 1

since cells all have special structure and function it is a challenge to coordinate all the functions in cells

Question 2

how do cells communicate?

Answer 2

Cells can signal to each 
other and interpret the 
signals they receive from 
other cells and the 
environment
Signals are most often 
chemicals

Question 3

Animals will utilize two distinct types of signaling to organize the cells of the body, what are the two types?

Answer 3

1. Electrical Signaling

2. Chemical Signaling

Question 4

what is one type/example of electrical signaling ?

Answer 4

Action potentials

 - Along an axon
 - Along the sarcolemma (plasma membrane of a muscle cell)

Question 5

what are 3 types of chemical signaling?

Answer 5

1. Neurotransmitters
   
   • Such as acetylcholine
2. Paracrine (localized)
3. Endocrine(long distance)
   
   • Hormones

Question 6

In local signaling, animal cells may communicate by direct contact- what is direct contact?

Answer 6

Animal cells have cell junctions that directly connect the cytoplasm of adjacent cells and Signaling substances in the cytosol can pass freely between adjacent cells

Question 7

what enables cells for direct contact?

Answer 7

cellular junctions and the structure of gap junctions
These structures enable cells in direct contact to communicate
This is one form of local signaling

Question 8

In many other cases, animal cells communicate using secreted messenger molecules that travel only short distances, what are the two types of secreted messengers?

Answer 8

Synaptic signaling
Paracrine signaling
In both of these forms chemical signals will be secreted from the cell

Question 9

where and when does Synaptic signaling occur?

Answer 9

Synaptic signaling occurs in the 
animal nervous system when a 
neurotransmitter is released in 
response to an electric signal

Question 10

In long-distance signaling, animals use chemical messengers referred to as?

Answer 10

hormones

Question 11

Hormonal signaling in animals is called ?

Answer 11

endocrine signaling;

specialized cells release hormones, which travel to target cells via the circulatory system

Question 12

The ability of a cell to respond to a signal depends on what?

Answer 12

whether or not it has a receptor specific to that signal

Question 13

what are Glands?

Answer 13

Specialized organ (or a group of cells) which manufacture and secrete chemical signals (hormones)

Question 14

what does Production of these chemical messages (from glands) allows for

Answer 14

the coordination of activities in multiple areas of the body

Question 15

Many of these glands (or cells) are associated with the integrating center (comparer) of negative feedback loops
Why?

Answer 15

because the physiological response is tied to negative feedback loops which send messages to other cells to maintain homeostasis.
it coordinates amount other cells for growth and development for bilateral symmetry

Question 16

what are three types of glands?

Answer 16

1. Exocrine glands
2. Endocrine glands
3. Mixed function glands

Question 17

what do Exocrine glands do? give 2 examples.

Answer 17

secrete their products into ducts that carry these products to other organs or outside the body

1. Salivary glands
2. Sweat glands

Question 18

what do Endocrine glands do? give 2 examples

Answer 18

secrete their products directly into the bloodstream

1. Pituitary gland
2. Thyroid gland

Question 19

what do Mixed function glands do? give one example

Answer 19

capable of both exocrine and endocrine secretion

1. Pancreas

Question 20

What are hormones?

Answer 20

Chemical signals that promote communication between cells, body parts, and even individuals

Question 21

what does it mean that hormones are targeted?

Answer 21

they will only interact with a target cell

target cell will be carried in the extracellular fluid or blood of an animal

Question 22

why must hormones exhibit complexity but yet be simple?

Answer 22

they have to be complex enough to avoid mixing up signals and they have to be simple enough to travel around the body

Question 23

what are Hormone Receptors?

Answer 23

Proteins of target cells in which a hormone will bind -
Once binding occurs a response will occur
and Internal conditions of cell could change triggering a response

Question 24

why is specificity of protein receptor to specific hormones

vital?

Answer 24

so that the hormone goes to the right place and coordinates the correct response.

Question 25

what are the two main classes of hormone receptors?

Answer 25

1. Internal receptors

2. External receptors

Question 26

what are Internal hormone receptors?

Answer 26

receptors 
within the cell; hormone must 
cross plasma membrane (they are small, non polar, and highly regulated.

Question 27

what are External hormone receptors?

Answer 27

protein 
receptors on the plasma 
membrane which bind 
hormones on extracellular 
face of the cell (polar, hydrophilic)

Question 28

what are the characteristics of a “good” hormone? (3)

Answer 28

1. complexity
2. stability
3. elicit a response

Question 29

Two methods of categorizing hormones.. what are they ?

Answer 29

1. Molecular: the type of molecule and 
its chemical nature

2. Behavior: specifically in regards to 
water, its hydrophobicity

Question 30

what is Hydrophobicity? what are the three classes of it?

Answer 30

Chemical nature of the molecule will determine how the hormone is moved through the body (i.e. blood) and the type of receptor it will interact with.

1. Hydrophobic or Lipophilic
2. Hydrophilic or Polar Hormones
3. Special Classes

Question 31

what are special classes?

Answer 31

not truly hydrophobic or hydrophilic

Question 32

what are Hydrophobic or Lipophilic hormones? give an example.

Answer 32

Non-polar molecules that hate water, are fat-soluble and love lipids
Examples:
All steroid hormones and some amine hormones

Question 33

As Hydrophobic or Lipophilic hormones do not dissolve in water how do we move them?

Answer 33

Bind to carrier molecules

Question 34

what are Hydrophilic or Polar Hormones? give at least one example

Answer 34

Water-soluble and Found in blood free and in active form
Examples:
All peptide hormones and many of the amine hormones

Question 35

since Hydrophilic or Polar Hormones are not able to pass through plasma membrane they are?

Answer 35

Surface receptors

Question 36

Hormones must be able to induce a response in the target– This process will vary between what two things?

Answer 36

1. hydrophilic and 2. lipophilic hormones

Question 37

what are the three Stages of Cell Signaling?

Answer 37

1. Reception
2. Transduction
3. Response

Question 38

what is Reception cell signaling?

Answer 38

In reception, the target cell detects a signaling molecule that binds to a receptor protein on the cell surface

Question 39

what is Transduction cell signaling?

Answer 39

In transduction, the binding of the signaling molecule alters the receptor and initiates a signal transduction pathway; transduction often occurs in a series of steps

Question 40

what is Response cell signaling?

Answer 40

In response, the transduced signal triggers a specific response in the target cell

Question 41

what are the main two differences between Hydrophilic and Lipophilic?

Answer 41

Hydrophilic
-Much faster time from reception to response
-Relatively short lived response
Lipophilic
-Slower than hydrophilic responses
because it has a harder time getting into the blood- it has extra steps / longer time but a longer lived response
-Much longer lived response