LECTURE 3: CHEMICAL SIGNALS IN ANIMALS

Question 1

Regulatory Mechanisms

Answer 1

1. Nervous System
2. 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

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

Answer 4

Animal hormones

Question 5

*Hormones reach all parts of the body,
but only __________ are equipped to
respond

Answer 5

target cells

Question 6

ex: ________________ is regulated by
hormones

Answer 6

Insect metamorphosis

Question 7

Two type of Glands in Vertebrate Endocrine System

Answer 7

1. Exocrine Gland
2. Endocrine Glands

Question 8

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

Answer 8

Exocrine glands

Question 9

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

Answer 9

Endocrine glands

Question 10

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

Answer 10

Target Cell Concept

Question 11

Hormones and other signaling molecules bind to ____________, triggering specific response pathways

Answer 11

target receptors

Question 12

Two Factors influencing the hormone concentration in the blood

Answer 12

1, Rate of Hormone Secretion into the blood
2. Rate of Removal of the hormone from the blood (metabolic clearance rate)

Question 13

Clearance of Hormones from the plasma include:

Answer 13

1. Metabolic Destruction
2. Binding with the tissue
3. excretion by the liver into the bile
4. excretion by the kidney into the urine

Question 14

Refers to the duration of time required to decrease the concentration of a circulating hormones by half

Answer 14

Half life of a hormones

Question 15

Chemical Messengers

Answer 15

Hormones

Question 16

Intercellular Communication

Answer 16

1. Endocrine Signaling
2. Synaptic Signaling

Question 17

secreted molecules diffuse into the bloodstream and trigger responses in target cells anywhere in the body

Answer 17

Endocrine signaling

Question 18

Types of Endocrine Signaling

Answer 18

1. Paracrine Signaling
2. Autocrine Signaling

Question 19

secreted molecules
diffuse locally and trigger a response in
neighboring cells

Answer 19

Paracrine signaling

Question 20

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

Answer 20

Autocrine signaling

Question 21

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

Answer 21

Synaptic signaling

Question 22

neurohormones diffuse into the
bloodstream and trigger responses

Answer 22

Neuroendocrrine signaling

Question 23

Secreted chemical signals include

Answer 23

o Local regulators
o Neurotransmitters
o Neurohormones
o Pheromones
o Hormones

Question 24

• chemical signals that travel over short
  distances by diffusion
• help regulate blood pressure, nervous system
  function, and reproduction
• divided into two types

Answer 24

Local Regulators

Question 25

Types of Local Regulators

Answer 25

Paracrine and Autocrine

Question 26

act on cells near the secreting cell

Answer 26

Paracrine signals

Question 27

act on the secreting cell itself

Answer 27

Autocrine signals

Question 28

proteins and polypeptides that stimulate cell proliferation

Answer 28

Growth factors

Question 29

Growth factors

Answer 29

Cytokines

Question 30

-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 30

Nitric oxide (NO)

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

Prostaglandins (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 -Acetylcholine (ACh) – muscle contraction

Answer 32

Neurotransmitters

Question 33

-secreted by neurosecretory cells -diffuse from nerve cell endings into the bloodstream -ADH (vasopressin) – increases water permeability of kidney’s collecting ducts and causes vasoconstriction (ADH)

Answer 33

Neurohormones

Question 34

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

Answer 34

Pheromones

Question 35

- 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 35

Hormones

Question 36

-Animal hormones - chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body - reach all parts of the body, but only target cells have receptors for that hormone

Answer 36

The Body’s Long-Distance Regulators

Question 37

________ _________ loop inhibits a response by reducing the initial stimulus, thus preventing excessive pathway activity

Answer 37

Negative feedback

Question 38

________ ______ reinforces a stimulus to produce an even greater response

Answer 38

Positive feedback

Question 39

The same hormone may have different effects on target cells that have

Answer 39

-Different receptors for the hormone - Different signal transduction pathways - Different proteins for carrying out the response

Question 40

A hormone can also have different effects in _______________

Answer 40

different species

Question 41

Different_____________________ in different cells can lead to different responses to the same signal

Answer 41

signal-transduction pathways

Question 42

Three major classes of molecules function as hormones in vertebrates:

Answer 42

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

Question 43

polypeptides and amines

Answer 43

water-soluble

Question 44

- steroid hormones and other largely nonpolar hormones

Answer 44

lipid-soluble

Question 45

are secreted by exocytosis, travel freely in the bloodstream, and bind to cell-surface receptors

Answer 45

Water-soluble hormones

Question 46

Water-soluble molecules bind to receptors in the ______________ of the target cells

Answer 46

plasma membranes

Question 47

has multiple effects in mediating the body’s response to short-term stress

Answer 47

epinephrine

Question 48

epinephrine binds to receptors on the plasma membrane of ________

Answer 48

liver cells

Question 49

triggers the release of messenger molecules that activate enzymes and result in the release of glucose into the bloodstream

Answer 49

Glucagon

Question 50

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

Answer 50

Lipid-soluble hormones

Question 51

Lipid-soluble hormones bind to receptors in the __________ or ___________ of the target cells

Answer 51

cytoplasm or nucleus

Question 52

response is usually a change in gene expression

Answer 52

Lipid-soluble molecules

Question 53

_______________ binds to its cytosolic receptor, a hormone-receptor complex forms that moves into the nucleus

Answer 53

steroid hormone

Question 54

receptor part of the complex acts as a _________________ of specific target genes

Answer 54

transcriptional regulator

Question 55

Signaling by any of these hormones involves three key events:

Answer 55

-Reception -Signal transduction -Response

Question 56

Water-soluble hormones respond

Answer 56

Gene regulation and Cytoplasmic response

Question 57

Lipid-soluble Hormones response in change in

Answer 57

Gene Expression7