part 2 section II Flashcards
neurotransmission
example of
example of paracrine system
neurotransmission
electrical stimulation of an neuron causes production of synaptic vessels containing acetylcholine in the presynaptic end of neuron
the acetylcholine is secreted into the synapse of exocytosis
neurotransmission
explain
neuron to muscle
transmission of electrical signal through a neuron to your muscle
depolarization of neuron in presynaptic area causes the release of these little vessicle that contain acytlcholone
secretory vessical form golgi complex
binds to acetylcholine receptor proteins on the surface of muscle cells which depolarizes the membrane by letting Na+ flow into the cell and K+ to flow out.
depolarization activities calcium channels in the muscle cells membrane, CA+ flows in and triggers contraction
Innate Immune Response to Microbes
example of paracrine system
bacteria trigger macrophages to release cytokines
cytokines act on nearby cells lining blood vessels to cause vasodilation
Other innate immune cells migrate to infection tissue to further fight the infection and contribute to healing
most signaling is
in the absence of disease most signaling is endocrine and paracrine. In cancer, autocrine signaling contributes to tumor progression
normal mammary epithelial cells
example of autocrine
normal mammary epithelia contain two cell types: one makes paracrine growth factors that cause the other cells type to proliferate during female menstrual cycle
ligands
chemical messengers (ligands) bind to specific protein receptors which are broadly classified by their cellular location
plasma membrane receptors
are located at the cell surface and are usually integral membrane proteins
- they bind ligand on their extracellular domain
- their ligand are hydrophilic molecules or proteins that cannon cross the hydrophobic plasma membrane
intracellular receptors
located in the cytoplasm or nucleus
- their ligand are hydrophobic and are able to cross the membrane
- In blood these hydrophobic ligands are bounded to carrier proteins
intracellular receptors type
belong to the nuclear receptor superfamily
Steroid/Vitamin/Thyroid receptors comprise a branch of this superfamily
Their ligands are hydrophobic and enter cells by simple diffusion
- steroids (glucorticoids, estrogen, progesterone, testosterone, mineralocorticoid)
Vitamin A (retinoids)
Vitamin D3
T3 thyroid hormone
steroid/vitamin/thyroid receptors
are ligand activated transcription facts
They bind their specific ligand in the cytoplasm or neckless and induce the a change in shape.
the change in shape uncovers a domain that binds specific DNA sequence and allows dimerization of two identical receptors.
the receptor enters the nucleus, binds to genes containing their DNA recognition sequence, and alters the amount of transcription
steroid/vitamin/thyroid receptors
key concept
the signal is transducer from outside the cell into the nucleus by the steroid/vitamin and its specific receptor
