Cells Communicate Movie: Play-by-Play

HOME

AMAZING CELLS

HOW CELLS COMMUNICATE DURING THE FIGHT OR FLIGHT RESPONSE

CELLS COMMUNICATE MOVIE: PLAY-BY-PLAY

One of the most remarkable examples of cell communication is the fight or flight response. When a threat occurs, cells communicate rapidly to elicit physiological responses that help the body handle extraordinary situations. The Cells Communicate movie depicts just some of the communication and responses involved in the fight or flight response.
Below is a detailed guide to events taking place in the movie.

Movie Time	Event
0:16	An environmental signal is perceived and initiates a signal in a primitive part of our brain called the amygdala. The amygdala relays the signal to another area of the brain called the hypothalamus.
0:25	Neurosecretory neurons from the hypothalamus release corticotropin-releasing hormone (CRH) into the hypothalamo-hypophyseal portal system. The hypophyseal portal system is the system of blood vessels that links the hypothalamus and the pituitary gland. When stimulated by CRH, corticotrope cells of the pituitary release ACTH (adrenocorticotropic hormone) into the bloodstream (green molecules).
0:38	Simultaneously, nerve impulses travel from the hypothalamus to the adrenal gland (atop the kidneys) via the splanchnic nerve in the sympathetic nervous system. Both the chemical signal (ACTH) and nerve impulse initiated in the hypothalamus will travel to the same place (the adrenal gland).
0:49	The splanchnic nerve impulse signals chromaffin cells in the medulla of the adrenal gland to release epinephrine (blue molecules) into the bloodstream. Epinephrine will travel to many different cell types.
0:54	The ACTH previously secreted by the pituitary gland reaches cells in the cortex of the adrenal gland.
1:01	ACTH docks on a MC2-R receptor of an adrenal cell and begins the cell signaling cascade that will eventually convert inter-cellular cholesterol to cortisol.
1:35	The newly-formed cortisol is promptly secreted through the cell membrane into the bloodstream. Cortisol begins signaling cascades in several cell types, resulting in an increase in blood pressure, increase in blood sugar levels, and suppression of the immune system.
1:42	We catch up with the epinephrine that was released earlier by the chromaffin cells in the adrenal gland. From here, the epinephrine will travel to several cell types, eliciting different responses.
1:45	Epinephrine binds to Alpha-1 adrenergic receptors on liver cells (hepatocytes) and triggers a signaling cascade initiating glycogenolysis. Individual glucose subunits are broken off of a glycogen molecule.
2:26	The newly-formed glucose diffuses through the cell membrane and enters the bloodstream. Glucose provides an immediate source of energy for muscle cells.
2:24	Epinephrine continues to travel in the bloodstream to the skin
2:42	Epinephrine binds to a receptor on an erector pilli smooth muscle cell. This causes a signaling cascade that contracts the muscle, raising the hair on the surface of the skin. The excitation of the erector pili muscle (called piloerection) also commonly occurs via norepinephrine secreted by nerve cells.
2:56	Epinephrine binds to Alpha-1 adrenergic receptors receptors on the surface of sweat gland cells, triggering a signaling cascade that contracts the gland, squeezing sweat to the skin’s surface. Epinephrine also acts to constrict capillaries near the skin surface to push blood inward to the organs. This is why skin may appear pale when frightened during the fight-or-flight response.
3:15	In the lungs, epinephrine sets off a signaling cascade that relaxes muscle cells surrounding the bronchioles to enable increased respiration.
3:26	Epinephrine can have opposite effects (contraction, or relaxation) depending on the type of receptor upon which it docks. Docking on alpha-1 adrenergic receptors on the erector pilli muscle causes contraction, while docking on beta-2 adrenergic receptors on bronchiole muscle cells cause relaxation.
3:51	Epinephrine also acts on the pacemaker cells of the heart (sinoatrial or SA node), stimulating them to beat faster. As a result, energy and messenger chemicals are circulated throughout the body at a faster rate. Unlike cardiac muscle cells, The specialized pacemaker cells in the SA node are small and round and have relatively few organelles or myofibrils.