Lecture 3: Chemical Signals in Animals

Question 1

Regulatory Mechanism

Answer 1

Nervous system and Endocrine System

Question 2

conveys high-speed
electrical signals along specialized cells
called neurons; these signals regulate
other cells

Answer 2

Nervous System

Question 3

secretes hormones that coordinate slower but longer-acting responses including reproduction,
development, energy metabolism, growth, and behavior

Answer 3

Endocrine System

Question 4

chemical
signals that are secreted into the
circulatory system and communicate
regulatory messages within the body

Answer 4

Animal Hormones

Question 5

Two Types of Glands

Answer 5

Exocrine glands and Endocrine glands

Question 6

secrete chemicals into ducts and the
effect is where the duct empties; sweat glands - sweat
(evaporative cooling)

Answer 6

Exocrine glands

Question 7

secrete chemical messengers
(hormones) into the blood for distribution throughout the
animal’s body and bind to specific hormone receptors.

Answer 7

Endocrine glands

Question 8

Experiment on hen

Answer 8

Arnold Adolph Berthold (1849)

Question 9

Human development regulation

Answer 9

Signaling pathways

Question 10

Signaling pathways are regulated by…

Answer 10

specific chemical signaling molecules

Question 11

• Hormones and other signaling molecules bind to
  target receptors, triggering specific response pathways
• Chemical signals bind to receptor proteins on target
  cells
• Only cells that respond to the signal

Answer 11

Target Cells

Question 12

Intercellular Communication

Answer 12

1. Endocrine Signaling
2. Paracrine Signaling
3. Direct Signaling

Question 13

Endocrine Signaling

Answer 13

Neuroendocrine

Question 14

Paracrine Signaling

Answer 14

1. Autocrine
2. Synaptic

Question 15

• secreted molecules diffuse into the bloodstream
  and trigger responses in target cells
  anywhere in the body.
• Relatively slow.

Answer 15

Endocrine Signaling

Question 16

neurohormones diffuse into the
bloodstream and trigger responses

Answer 16

Neuroendocrine

Question 17

• secreted molecules
  diffuse locally and trigger a response in
  neighboring cells.
• Quick response.

Answer 17

Paracrine Signaling

Question 18

secreted molecules
diffuse locally and trigger a response in
the cells that secrete them

Answer 18

Autocrine

Question 19

neurotransmitters diffuse across synapses
and trigger responses in cells of target
tissues

Answer 19

Synaptic/Neural Signaling

Question 20

• for some signals to be
  received, the cells must be in direct contact.
• Either via interacting membrane proteins on two
  different cells, or through special cell-cell junctions.

Answer 20

Direct Signaling

Question 21

signals act on cells near the
secreting cell

Answer 21

Paracrine

Question 22

signals act on the secreting cell
itself

Answer 22

Autocrine

Question 23

proteins and
polypeptides that stimulate cell
proliferation

Answer 23

Growth Factors

Question 24

play a role in immune
responses

Answer 24

Cytokines

Question 25

Fast Signaling

Answer 25

Juxtacrine Signaling

Question 26

For Animals

Answer 26

Gap Junctions

Question 27

For Plants

Answer 27

Plasmodesmata

Question 28

- acts as a neurotransmitter when secreted by neurons - kills bacteria and cancer cells when secreted by WBCs. - dilates the walls of blood vessels when secreted by endothelial cells

Answer 28

Nitric Oxide (NO)

Question 29

The mechanism of erection of the penis involves the release of nitric oxide (NO) in the ________ during sexual stimulation.

Answer 29

Corpus Cavernosum

Question 30

enhances the effect of NO by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for the degradation of cGMP in the corpus cavernosum

Answer 30

Sildenafil (Viagra)

Question 31

- modified fatty acids - secreted by the placenta stimulate uterine contractions during childbirth - promote fever and inflammation and intensify the sensation of pain - regulate aggregation of platelets (early step in blood clot formation)

Answer 31

Prostaglandine (PGs)

Question 32

- secreted by neurons at many synapses - diffuse a very short distance - bind receptors on target cells - play a role in sensation, memory, cognition, and movement

Answer 32

Neurotransmitters

Question 33

muscle contraction

Answer 33

Acetylcholine (ACh)

Question 34

- secreted by neurosecretory cells -diffuse from nerve cell endings into the bloodstream

Answer 34

Neurohormones

Question 35

increases water permeability of kidney’s collecting ducts and causes vasoconstriction (ADH)

Answer 35

ADH (vasopressin)

Question 36

- chemical signals that are released from the body and used to communicate with - ther individuals in the species - mark trails leading to food - defining territories - warning of predators - attracting potential mates

Answer 36

Pheromones

Question 37

- chemicals that transfer information and instructions between cells in animals and plants - body’s chemical messengers - regulate growth and development - control the function of various tissues - support reproductive functions - regulate metabolism - slow acting but long lasting

Answer 37

Hormones

Question 38

chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body

Answer 38

Animal Hormones

Question 39

Three major classes of molecules function as hormones in vertebrates:

Answer 39

- Polypeptides (proteins and peptides) - Amines derived from amino acids - Steroid hormones

Question 40

water-soluble

Answer 40

polypeptides and amines

Question 41

lipid-soluble

Answer 41

steroid hormones and other largely non-polar hormones

Question 42

Water-soluble hormones are secreted by _______, travel freely in the bloodstream, and bind to cell-surface receptors

Answer 42

Exocytosis

Question 43

They bind to receptors in the _______ of the target cells

Answer 43

plasma membranes

Question 44

- has multiple effects in mediating the body’s response to short-term stress - binds to receptors on the plasma membrane of liver cells - triggers the release of messenger molecules that activate enzymes and result in the release of glucose into the bloodstream

Answer 44

Epinephrine

Question 45

hormones diffuse across cell membranes, travel in the bloodstream bound to transport proteins, and diffuse through the membrane of target cells

Answer 45

Lipid-soluble

Question 46

Signaling by any of these hormones involves three key events:

Answer 46

1. Reception 2. Signal Transduction 3. Amplification 4. Response

Question 47

detection of a signal in the environment

Answer 47

Reception

Question 48

activating a series of proteins inside the cell

Answer 48

Signal Transduction

Question 49

change in behavior that occurs inside the cell

Answer 49

Response