Chemical Signals in Animals Flashcards
Regulatory systems in the body that maintains homeostasis
Nervous and Endocrine system
Chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body.
Animal Hormones
Cells that are equipped to respond to the hormone signals
Target Cells
Two types of gland in the vertebrate endocrine system
Exocrine and Endocrine glands
Secretes chemical into ducts and the effect happens where the duct empties (e.g. sweat glands, tear ducts)
Exocrine glands
Secretes chemical messengers into the bloodstream for distribution throughout the animals body and bind to specific hormone receptors.
Endocrine glands
Human development are regulated by various _______________
Signaling pathways
These are responsible for activating the signaling pathways
Specific chemical signaling molecules
They are the only ones responding to a specific hormones, chemical signals, and other signaling molecules that binds to their receptor protein.
Target Cells
Types of Intercellular Communication
- Endocrine Signaling
- Paracrine Signaling
- Direct Signaling
Signaling that secretes molecules that diffuse to the bloodstream and trigger responses in target cells anywhere in the body.
Endocrine Signaling
A subclass of Endocrine signaling where it is the neurosecretory cell that diffuses neurohormones to the bloodstream and trigger responses
Neuroendocrine Signaling
Signaling molecules that are secreted diffuse locally and triggers response from neighboring cells. Quick response
Paracrine Signaling
A paracrine signaling subclass where the locally secreted molecules trigger a response directly to the cell that secrete them.
Autocrine Signaling
A subclass paracrine signaling where neurotransmitters are diffused by neurons diffuse across synapses and trigger responses from target cells.
Synaptic Signaling/Neuronal Signaling
Signaling by direct contact of target cells, interacting by either membrane proteins on two different cells or through special cell-cell junctions
Direct Signaling
Three(3) types of Direct Signaling
Juxtacrine Signaling, Gap Junction, Plasmodesmata Signaling (plants)
Different types of secreted chemical signals
- Local regulators
- Neurotransmitters
- Neurohormones
- Pheromones
- Hormones
Chemical signal that travel over a short distance by diffusion. Regulates the blood pressure, nervous system function, and reproduction
Local Regulators
Two types of local regulator chemical signals
Paracrine and Autocrine
Local Regulator that are made up of proteins and polypeptides that stimulate cell proliferation
Growth Factors
Plays a role in the body’s immune system response
Cytokines
A neurotransmitter that is secreted by white blood cells to kill bacteria and cancer cells. Also dilates the walls of blood vessel when secreted by endothelial cells.
Nitrous Oxide
Secretes nitrous oxide to kill bacteria and cancer cells
White Blood Cells
When secreted by __________, nitrous oxides acts to dilate the walls of the blood vessels
Endothelial cells
Erection of the penis happens when nitrous oxide is released in the ___________________
corpus cavernosum
Enhances the effects of nitrous oxide in penis erection by inhibiting phosphodiesterase type 5 (PDE5)
Sildenafil(Viagra)
Responsible for the degradation of cGMP in the corpus cavernosum where nitrous oxide is released for penis erection.
Phosphodiesterase type 5 (PDE5)
A local regulator made of modified fatty acids that are secreted by the placenta to stimulate uterine contractions during childbirth. It also promotes fever and inflammation to intensify the pain and regulate aggregation of platelets.
Prostaglandins
Secreted by the neurons at many synapses and diffuse at very short distances. Plays a role in sensation, memory, cognition, and movement
Neurotransmitters
Neurotransmitter that is responsible for muscle contraction
Acetylcholine(ACh)
Secreted by the neurosecretory cells that diffuse from their nerve endings towards the bloodstream.
Neurohormones
A type of neurohormone that increases the water permeability of kidney’s collecting ducts and causes vasoconstriction
ADH(vasopressin)
Chemical signals that are released from the body and used to communicate with other individuals in the species.
Pheromones
Chemicals that transfer information and instructions between cells in animals and plants. Body’s chemical messengers that regulates: growth and development, function of various tissues, support reproductive functions, and regulates metabolism. Slow acting but long lasting.
Hormones
Chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body
Animal Hormones
Two types of feedback regulation
Positive and Negative Feedback
Inhibits a response by reducing the initial stimulus, thus preventing excessive pathway activity
Negative Feedback
Reinforces a stimulus to produce an even greater
response.
Positive Feedback
Effects of hormone may be affected by:
- Different hormone receptor
- Different signaling transduction pathways
- Different proteins that carry out the response
Different ______________ pathways in different
cells can lead to different responses to the same
signal.
Signal-transduction pathways
Chemical classes of hormones
- Polypeptides
- Amines derived from amino acids
- Steroid hormones
Water-soluble hormones
polypeptides and amines
Lipid-soluble hormones
Steroid Hormones
Hormones that are secreted by exocytosis, travel
freely in the bloodstream, and bind to cell-surface receptors
Water-Soluble hormones
Triggers the release of messenger molecules that activate enzymes and result in the release of glucose into the bloodstream.
Epinephrine
Hormones that diffuse across cell membranes, travel in the bloodstream bound to transport proteins, and diffuse through the nuclear membrane of target cells.
Lipid-soluble hormones
They bind to receptors in the cytoplasm or nucleus of
the target cells
Lipid-soluble hormones
They bind to receptors in the plasma membranes of the target cells
Water-soluble hormones
A hormone-receptor that moves into the nucleus when a steroid hormone binds into it
Cytosolic receptor
Receptor part of the cytosolic complex acts as a
Transcriptional regulator of specific target genes
An enzyme complex that forms when a cytosolic receptor binds with a Lipophilic hormone
Hormone-receptor complex
Three key events of hormone signaling
- Reception
- Signal Transduction
- Response
Activating a series of proteins inside the cell
Signal transduction
Detection of a signal in the environment
Reception
Change in behavior that occurs inside the cell
Response
Refers to the duration of time required to decrease the concentration of a circulation hormone in half
Half life of a hormone
Factors influencing hormone concentrations in the blood
- Rate of hormone secretion
- Rate of hormone removal
Clearance or removal of hormones in the plasma membrane include:
- Metabolic destruction
- binding with the tissues
- excretion by the liver into the bile
- excretion by the kidneys into the urine
