Chapter 6 Flashcards
What are effectors?
Muscles and other tissues controlled by integrating centre
What is the pathway of cell-to-cell communication?
Input, integrating, output, response
What are the proteins of the body
The bodies workhorse
What are electrical signals
They have the ability to change cell membrane potential
What are chemical signals
Molecules secreted by cells
and received by target cells (ligands)
Gap Junctions
Clusters of intercellular channels that allow direct diffusion of ions and small molecules between adjacent cell
What are Gap Junctions?
(localized communication)
Allows direct cytoplasmic transfer of electrical and chemical signals between adjacent cells
What are Contact-Dependant molecules? (localized communication)
Surface molecules on one cell membrane bind to surface molecules on another cell membrane
Autocrine vs Paracrine (localized communication)
Autocrine - signaling regulates cellular growth and development
Paracrine - signaling is involved in immune responses and blood clotting
What is Long Distance Communication?
Usually between the endocrine and nervous system, them and electrical signals carried by nerve cells
What do gap junctions create?
Cytoplasmic Bridges
What is the Endocrine System? (long distance)
Hormones transport system, into blood or target cells with the correct receptors
What is a neurotransmitters? (long distance)
Chemicals from neutrons that diffuse across the small gap in target cells
What is a neurohormone? (long distance)
Chemicals released by neurons into blood for action at distant targets
What does crine mean?
Secretion
What are CAM’s?
Cell Adhesion Molecules
Synchronous Contraction
Gap junctions where electrical signals are rapidly transmitted via protein pores
Desmosomes
Surrounds sarcomeres and allows force to be transferred
Where are gap junctions found?
Heart and smooth muscle
What is a Sarcomere?
The basic contractile unit of muscle fibre
Can long distance communication be electrical or chemical?
Yes
Where is neurocrine release from?
Neurons
What are cytokines?
Peptides that are both local and long-distance communication
Lipophobic Signal Molecules do what?
They diffuse and then bind to cytosolic receptors or nuclear receptors
What are intracellular signal receptors?
Stimuli with ligands and IC receptors and then bind to the response elements of DNA
What does Transduction mean?
The process by which a virus transfers genetic material from one bacterium to another
What are first messengers?
First messengers are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, and serotonin
What are second messengers?
Small molecules and ions that relay signals received by cell-surface receptors to effector proteins
What are cascades?
Transduction pathways form an cascade like a ladder
What are amplification?
Small amount of signal to have a large effect
How many categories are there of membrane receptors?
- receptor-channel; binding opens or closes channel
- G protein
- receptor- enzyme; activates IC enzyme
- integrin receptor; alters enzyme or cytoskeleton
What are G protein-coupled receptors? (GPCR)
Opens ion channels and alters enzyme activities
How does signal transduction work using g-proteins?
- molecule binds to GPCR activating g-protein
- g-protein turns on adenylyl cyclase, and amplifier enzyme
- AC then converts ATP to cyclic AMP
- cAMP activates protein kinase A
- Protein kinase A phosphorylates other proteins leading to cellular response
What is a TK receptor and what does it do? Who uses this?
Tyrosine kinase transfers a phosphate group from ATP to tyrosine. Used by insulin
Does calcium work as an intracellular messenger?
It does, calcium induces through gated channels, gets released within cardiac muscles, store in ER
What is an ephemeral signal molecule?
A soluble gas are short acting paracrine or autocrines, the best known one is NO. Activates cGMP
Does target response depend on the target receptor?
Yes
