LECTURE 3 Flashcards
Two regulatory mechanism
- nervous system
- endocrine system
_____ - conveys high-speed
electrical signals along specialized cells
called neurons; these signals regulate
other cells
Nervous system
____ - secretes hormones
that coordinate slower but longer-acting
responses including reproduction,
development, energy metabolism, growth,
and behavior
endocrine system
_ are chemical
signals that are secreted into the
circulatory system and communicate
regulatory messages within the body
Hormones
Hormones reach all parts of the body,
but only ____ are equipped to
respond
target cells
Insect metamorphosis is regulated by
____
hormones
Two types of gland
- exocrine glands
- endocrine glands
____ - secrete chemicals into ducts and the
effect is where the duct empties; sweat glands - sweat (evaporative cooling)
Exocrine glands
____ - secrete chemical messengers
(hormones) into the blood for distribution throughout the animal’s body and bind to specific hormone receptors
endocrine glands
exocrine glands secrete chemicals into ___
ducts
Endocrine glands secrete chemical messengers to ____
blood
In humans, our
development is
regulated by
various ______
signaling
pathways
These signaling
pathways are activated by _____
specific chemical signaling molecules
Hormones and other signaling molecules bind to ____, triggering specific response pathways
target receptors
Types of Intercellular Communication
- Endocrine Signaling
- Paracrine Signaling
- Direct signaling
_____ secreted molecules diffuse into the bloodstream and trigger responses in target cells anywhere in the body.
-Relatively slow.
endocrine signaling
_____ neurohormones diffuse into the
bloodstream and trigger responses
Neuroendocrine signaling
In Neuroendocrine signaling, the ___ diffuse into the bloodstream and trigger responses
neurohormones
Type of endocrine signaling
- Neuroendocrine signaling
Types of paracrine signaling
- Autocrine signaling
- synaptic SIgnaling
____ secreted molecules
diffuse locally and trigger a response in
neighboring cells.
-Quick response.
Paracrine signaling
____ secreted molecules diffuse locally and trigger a response in the cells that secrete them
Autocrine signaling
In ____ neurotransmitters diffuse across synapses and trigger responses in cells of target tissues
Synaptic/Neuronal signaling
In Synaptic/Neuronal signaling, _____
diffuse across synapses and trigger responses in cells of target
tissues
neurotransmitters
____ : 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
Direct signaling
Types of direct signaling
- Juxtacrine signaling
- Signaling through gap junctions
- Signaling through plasmodesmata
Types of secreted signaling molecules:
- Local regulators
- Neurotransmitters
3.Neurohormones
4.Pheromones - Hormones
____ chemical signals that travel over short
distances by diffusion
- help regulate blood pressure, nervous system function, and reproduction
Local regulators
Local regulators are divided into two types:
- Paracrine signals
- Autocrine signals
_____ act on cells near the
secreting cell
Paracrine signals
____ act on the secreting cell itself
Autocrine signals
______ proteins and
polypeptides that stimulate cell
proliferation
Growth Factors
_____ play a role in immune responses
Cytokines
- 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
Nitric oxide (NO)
- 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)
Prostaglandins
prostaglandins is what type of signaling molecule?
Local regulator
- 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
Example: Acetylcholine (ACh) – muscle contraction
Neurotransmitter
- secreted by neurosecretory cells
-diffuse from nerve cell endings into
the bloodstream
Nuerohormones
Example of Neurotransmitter
Acetylcholine - for muscle contraction
Example of neurohormones
ADH (vasopressin) – increases
water permeability of kidney’s
collecting ducts and causes
vasoconstriction (ADH)
A type of neurohormones ____ that increases water permeability of kidney’s
collecting ducts and causes
vasoconstriction (ADH)
ADH (vasopressin)
____ chemical signals that are released from
the body and used to communicate with
other individuals in the species
Pheromones
Use of pheromones
- Mark trails leading to food
- defining territories
- warning of predators
- attracting potential mates
____ chemicals that transfer information and
instructions between cells in animals and
plants
Hormones
Use of hormones:
- body’s chemical messengers
- regulate growth and development
- control the function of various tissues
- support reproductive functions
- regulate metabolism
- slow acting but long lasting
____ -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
Animal hormones
_____ inhibits a response by reducing the
initial stimulus, thus preventing excessive pathway activity
o Negative
feedback loop
- reinforces a stimulus to produce an
even greater response
Positive
feedback
The same hormone may have different
effects on target cells that have:
- Different receptors for the hormone
- Different signal transduction pathways
- Different proteins for carrying out the response
same hormones, but different receptors means
different effect to the muscle, tissue, or organ
same hormones, same receptor, but different impact to different organs
korek
Three major classes of molecules function
as hormones in vertebrates:
- Polypeptides (proteins and peptides)
- Amines derived from amino acids
- Steroid hormones
water-soluble class of hormone
polypeptide and amines
Lipid soluble class of hormones
steroid hormones and other
largely non-polar hormones
example of polypeptide
insulin and epinephrine
example of steroids
cortisol and thyroxine
Insulin-like growth factors major sites of production?
liver and cartilages
Insulin-like growth factors major actions?
growth and cell division
Nitric oxide major site production:
- endothelium of blood vessels
- neurons
- macrophages
Nitric oxide major actions
dilation of blood vessel
endothelins major sites productions ?
endothelium of blood vessels, other organs
endothelins major actions
constrictions of blood vessels and other effects
Platelet-derived growth factor major sites of production
- platelets
- macrophages
- vascular smooth muscle cells
Platelet-derived growth factor major action
cell division with blood vessel
epidermal growth factors major sites production
epidermal tissues
epidermal growth factors major actions
cell division in wound healing
Neurotrophins major site of production
- schwann cells
- neurons
Neurotrophins major actions
regeneration of peripheral nerves
Bradykinin major site production
endothelium of blood vessels
Bradykinin major actions
dilation of blood vessels
Interleukins (cytokines) major site production
- Macrophages
- lymphocytes
Interleukins (cytokines) major actions
regulation of immune system
Prostaglandins major site production
many tissue
___ hormones are secreted by exocytosis, travel freely in the bloodstream, and
bind to cell-surface receptors
- They bind to receptors in the
plasma membranes of the target
cells
Water-soluble hormones
____ has multiple effects in mediating the body’s response to short-term stress
- triggers the release of messenger molecules
that activate enzymes and result in therelease of glucose into the bloodstream
epinephrine
____ diffuse across cell membranes, travel in the bloodstream bound to transport proteins, and diffuse through the membrane of target cells
Lipid-soluble hormones
Signaling by any of these hormones
involves 4 key events:
- Reception
- Signal Transduction
- Response
- Amplification
_____ - detection of a signal in
the environment
Reception
____ – activating a
series of proteins inside the cell
Signal transduction
____ – change in behavior that
occurs inside the cell
Response
____ refers to the duration of the time required to decrease the concentration of a circulating hormone by half
half life of a hormone
_____ involves the hormones- secreting tissues and organs of the body
endocrine system
