Coursecram Flashcards
what is the endocrine system?
- all the hormone secreting cells of an organism
- composed of endorcrine and neuroendocrine glands
- these glands secrete their hormones and neurohormones into body fluids (blood, hemolymph, etc. )
- think “within the body”
what is histamine?
- local regulator
- regulation of immune response and and inflammation
what are local regulators
signals that act like hormones but never enter any circulatory system
what are pheromones
they are signals that leave the organism and act at a distance on another organism
what are the 3 signalling strategies?
- autocrine (self signal)
- paracrine (signal beside it, histamine)
- endocrine (within)
what are the four groups of hormones?
- amino acid derivatives: dopamine, melatonin, thyroid hormones, adrenaline
- peptide hormones: proteins, prolactin,insulin
- steroid: cholestoral derivatives, sex hormones, cortisol
- fatty acid derivatives: in insects
what type of soluble are steroid hormones?
lipid soluble
what are the unique properties and receptor location of peptide hormones?
- encoded by genes
- soluble in blood
- receptors found on the plasma membrane
what are the unique properties and receptor location of steroid hormones?
- insoluble in blood
- need carrier proteins
- made by enzymes
- receptors are found in the cytoplasm
what are the steps in the endocrine signalling pathways?
- synthesis: translation and enzymatic
- transport: either soluble or insoluble (need carrier proteins)
- reception: only cells with the appropriate receptor expressed can respond
- transduction
- response
what are the 2 types a receptor can be?
- angonists: stimulatory
- antagonist: inhibitory
what are the 2 general kinds a receptor can be?
- angonists: stimulatory
- antagonist: inhibitory
what can hormone concentration affect for receptors?
activity
what are peptide hormones synthesized by?
genes that are expressed
what are steroid hormones synthesized by?
enzymes
which can travel through the blood stream? soluble or insoluble hormones
- soluble: can travel
- insoluble: bind carrier proteins in the blood (Albumin and Globulins)
what are signal transduction pathways?
- extracellular signals that produce one or more effects in structure, function, of the gene expression profile of the target cell
what are the types of receptors? what are the types thar use second messengers?
use 2nd messengers
* GCPR
* Ligand gated ion channels
* receptor enzyme
don’t use it
* intracellular receptor (influences gene expression- steroids)
what do second messengers do?
amplify response and most signalling cascades use them
what are protein kinases?
act on each other and transmit signals by a casecase of phorphorylations that cause conformational change in phosphorylated protein
what does phosphorylation usually change in a protein?
changes it from inactive to active form
what are the antagnostic hormones in the human endocrine system? what is their general roles
- general role: maintain homeostasis
Regulation of Glucose
* insulin: decreases blood sugar levels by stimulating uptake at the tissues
* glucagon: increases blood sugar levels by stimulating glucose released by the liver into the blood
Regulation of Sodium Levels
* ADH: less water in urine
* ANP: more sodium in urine
* alsosterone: more sodium in urine
what happens when you eat, in terms of insulin?
- blood sugar spikes
- insulin released from pancres
- causes glucose to be taken out of the blood (by tissues) and stuffed into the cells
what happens when you fast, in terms of glucagon?
- blood sugar is depelted
- glucagon released
- releases glucose from liver and into the blood
what does increased sodium levels cause?
- stimulates hypothalamus
- which stimulates the posterior pituitary
- which release ADH
- ADH causes for more water to be abosrbed, and for there to be less water in urine
what does the hypothalamus do?
- stimulate release of hormones into the blood
- secretes tropic hormones
- stimulates the posterior pituitary
- pupper master
what is the anterior pituitary controlled by?
tropic hormones
describe the pathway of cortisol.
- hypothalamus releases CRH which is a tropic hormone which stimulates the release of other hormones
- the anterior pituitary then releases ACTH to the adrenal cortex
- this then releases cortisol: stress
what is phytoestrogens?
plants posses estrongen like compounds, which can cause for vertebrates to become feminized due to too much exposure from phytoestrogens
what are the 4 functions of the nervous system
- recieve external and internal signals
- transmit external and internal signals
- integrate/interpret all signals
- coordinate/command an action/response to those signals
what are the two components of the nervous system and their function?
- CNS: brain and nerve cord
- PNS: all neurons and their projections outside the CNS
what is integration carried out by?
interneurons
what is the general structure of a neuron?
- dendrites: recieve inputs from other neurons or the environment
- nucleus
- cell body/soma: has nucleus and organelles
- nodes of ranveir: location of action potential
- axon: transmit impulses
- myelin sheath: allow saltatory/jumping conductions
- axon termini
what is a nerve tract?
a bundle of axons
what is a ganglion
a collection of neuron cell bodies
what is the myelin sheaths role, and what is it formed by?
- formed by glial cells
- acts as insulating material
where does the action potential run down and go?
runs down the azon and then it has to be relayed off to the next cells, when it reaches the axon termini
how are the glial cells subdivided? what is each of their functions?
- microglia: defense and savenging of the immune cells of the CNS
- astrocytes: maintenance and support
- oligiodendrocytes: insulating of neurons for electrical transmission, outside of the CNS called schwan cells, form the myelin sheath
is a reflex arc voluntary or involuntary?
involuntary
what is an effernt neuron
motor neuron
what were the steps in evolution related to the nervous system?
- more nerves and nerve bundles
- concentration of nerves (ganglia)- cell bodies organized
- specialization of function of cells
- more complex synaptic contacts
- trend toward cephalization (creating a brain)
what is cephalization?
tendency toward bundles of nerves around the head
what is the hindbrain
- survive
- central pattern generator (stores the pattern of neuronal connections)
what is the midbrain?
- router
- conector to forebrain
vision and hearing
what is the forebrain?
- decision maker
- center for integration of complex pathways
how is the PNS seperated, and what are their roles?
- sympathetic: fight or flight
- parasympathetic: rest and digest
what is the common neurotransmitter of the PNS?
adrenaline
what are the differences in duration for hormonal vs neural stimulation of fight or flight?
- neural stimulation of fight or flight is immediate and short
- hormonal stimulation of fight or flight is a longer lasting response
*
what is the resting membrane potential in resting neurons?
-70mV
is there more sodium or potassium inside or outside of the cell?
- more sodium outside
- more potassium inside
what is an action potential?
- if the stimulus is strong enough the neuron fires a nerve impulse, which is an action potential
- action potentials move along the axon, to cell body, to synaptic termini
explain the steps of an action potential.
- reach threshold: due to small depolorizations
- rapid depolarization: fast opening of sodium channels open
- repolarization beginds: small opening of potasssium channels open
- repolorization continues
- hyperpolarizations: potassium channels are slow to close, so too much flows out, making it very negative
- resting potential restored: sodium/potassium pump is always on
what does the speed of action potential conduction depend on?
- axon diameter: broader is faster, due to less resistance (in bigger one)
- myelination: myelination is faster
what are synapses?
junctions that control the communication between a neuron and another cell (neuron or not)
what is the transmitting cell called?
presynaptic cell
what is a recieving cell called
the post synaptic celll
what is acetylcholine?
- type of neurotransmitter
- one of the most widepsread
- released at neuromuscular junctions
- excitatory in brain and skeletal muscles
- inhibitory in cardiac muscles
what happens when the action potential reaches the synaptic termini?
releases chemical messengers (neurotransmitters)
what do neurotransmitters do with an action potential?
- bind receptors in the post synaptic cell membrane and trigger other changes (open ion channels, initiaye other signalling changes)
- after activating their receptors, neuro transmitters are rapidly degraded or re abosorbed by pre synaptic cell (limits duration of stimulus)
describe what happens in the pre and post synaptic cell?
- AP opens voltage gated calcium channels
- calcium influx triggers vesicles docking (exocytosis event) and neurotransmitter is released in synapse
- neuro trans bind to post synaptic cell at receptor and these initate a response (inhibitory or excitory)
what can neurotransmitter signalling be stopped by?
degredation at the synapse or reuptake
what is sumation?
the integration of both stimulatory and inhibitory stimuli
what does a NT cause at an excitatory synapse?
a slight depolarization of the membrane and is called an excitatory post synaptic potential (EPSP)
what does a NT cause at an inhibitory synapse?
a hyper polarization of the membrane and it is called an inhibitory post synaptic potrntial (IPSP)
what determines if a post synaptic neuron will fire an AP>
the summation of all the EPSP and IPSP that reach the axon hillock at any time
what is the axon hillock
where the axon originates and where the voltage gated sodium channels are
what does IPSP cause?
repolarize cell slightly, make more neg
what does EPSP cause?
depolarize cell slightly, make more pos
what is learning?
the process of acquiring new info, and making new connection
what is memory?
process of storing info in stable neuronal connections, maintaining connections
what is plasticity?
ability to change synaptic connections and function properties of neurons
how does plasticity strengthen the communications between two neurons?
making more connections or reinforcing existing connections
what is the hot pepper receptor type?
heat receptor
what is muscle tissue responsible for?
the generation of force and motion essential for many life purposes including: locomotion, circultion, digestion and the manipulation of objects
what is the most abundant tissue in the vertebrae body?
muscles
what is the organization of muscles?
- tissue is arranged into bundles of muscle fibres
- muscle fibres are comprised of thinner threadlike structures caled myofibrils
- myofibrils are made up of individual actin (thin) and myosin filaments (thick)
what are the main proteins responsible for contraction of muscle fibers?
actin and myosin
how is force generated?
- when myosin pulls the actin polymer which causes the thick filament to slide over the thin filament
- a cross bridge forms between actin and myosin
- AP is hydrolysed, releasing enegy to the myosin head
- the resulting molecular changes in myosin cause the powerstroke
- interacting is described by slidng filament model
what is actin and what is myosin (think in terms of common function. symbol)
actin is the cable
myosin is the engine