Control through the Nervous and Endocrine System Flashcards
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Differences between the Hormonal (Endocrine) and Nervous system?
Hormonal system.
blood transport/slow/chemical communication/only it’s target responds/widespread response/slow response/lasting response.
Nervous System.
neurones transport/fast/nervous communication/nerve impulse specifically targeted/localised response/rapid response/short lived response.
Differences between the Sympathetic and Parasympathetic Nervous system?
Sympathetic - Speeds up everything so causes stimulation.
Parasympathetic - Slows down everything so causes relaxation.
Saltatory conduction?
Leaping of action potential across nodes of ranvier.
Difference between endocrine and exocrine?
Endocrine - Secretes into blood system.
Exocrine - Secretes but is already within the organ its targeting so can take immediate effect.
How do you properly spell Oestrogen?/Estrogen?
Oestrogen - because were in England.
What does homeostasis literally mean?
Homeo - the same
Stasis - stand still
Homeostasis - ‘Stay the same’
Define homeostasis.
Process maintaining the internal environment within defined limits, irrespective of the external environment.
Process of negative feedback during body temperature drop?
- Decreased body temperature
- Blood cooler than hypothalamic set point.
- Activates heat promoting centre in hypothalamus.
- Skin blood vessels contract - blood diverted from skin blood capillaries to deeper tissue - minimises heat loss from skin surface.
- Skeletal muscles contract to cause shivering which generates heat.
- Body temp increases - blood temp increases - hypothalamus heat promoting centre shuts off.
- Homeostasis achieved.
Process of negative feedback during body temperature rise?
- Increased blood temperature.
- Blood warmer than hypothalamic set point.
- Activates heat loss center in hypothalamus.
- Sweat glands secrete perspiration which evaporates by body heat and cools it.
- Skin blood vessels dialate - capillaries flushed with warm blood - heat radiates from skin surface.
- Body temperature lowers - blood temperature lowers - hypothalamus heat loss centre ‘shuts off’.
- Homeostasis achieved.
Basic process of negative feedback?
Tbh not sure if you need to know this or not
- Control centre detects that control variable’s set point has fluctuated. e.g body temperature drops below homeostasis.
- Appropriate effector used to combat the flux in the control variable. e.g skin capillaries
- Increase in control variable causes events (e.g shivering) that reduce the control variable fluctuation so it may refer back to its set point.
- Control variable refers back to set point.
- Control center detects the control variable’s set point has been achieved (homeostasis).
Why is negative feedback negative?
Because the deviation is a bad thing - so must be combated to bring the controlled variable back to normal. - so the body goes against the deviation so its negative.
e.g we want normality = 0
Deviation makes it so body goes -1,-2,-3,-4
Body combats this by going other direction so +1,+2,+3,+4 and keeps doing this until it gets to 0 which is normal. So its negative as its combating by going in opposite direction of deviation. (Obviously works both ways deviation can be + and body can be - as long as it combats to reach 0 its negative).
True or false? Positive feedback mechanisms are not homeostatic?
True.
Why is positive feedback positive?
Deviation from the normal occurs - and the body’s response is to make the deviation even greater. So it’s non-combatative and positive for body so its called positive.
e.g. Deviation from normal is +1,+2,+3,+4 body’s response is to support deviation so body goes +5,+6+7+8 ect.
What does the endocrine system involve?
Hormone activity.
What activity does the nervous system involve?
Impulse activity.
What does the nervous system do? What is it important for?
Senses and reacts appropriately to changes inside and outside the body. - Important for homeostasis.
Examples of internal and external sensory receptors?
Internal - Chemoreceptors/baroreceptors/osmoreceptors
External - sight/hearing/smell/taste/touch
What do chemoreceptors, baroreceptors and osmoreceptors detect?
Chemicals (pretty much hormones) - ‘chemo’receptors
Baroreceptors - pressure
Osmoreceptors - water ‘osmo’ as in osmosis lol.
What makes up the central nervous system?
Brain and spinal cord.
What do somatic and autonomic mean?
Somatic - voluntary effector action e.g skeletal muscle. can control
Autonomic - involuntary effector action e.g heart beating cant control.
Examples of effector organs? Both somatic and autosomal.
Somatic - Skeletal muscle
Autosomal - Cardiac muscle/Smooth muscle/Glands
All components of nervous system?
Central nervous system - Brain and Spinal chord.
Peripheral Nervous system (below)
- Sensory pathways (end)
- Motor pathways - somatic nervous system (end)
- Motor pathways - Autonomic nervous system - sympathetic division OR parasympathetic division
Brain stem? What does it do?
- Connects spinal chord to thalamus and cerebrum.
- Controls involuntary activities e.g respiration
Cerebellum? What does it do?
-Controls fine motor movements by coordinating voluntary decisions with the body’s response e.g balance.
Tell me about the Cerebrum.
Cerebrum processes information from the senses, to direct all voluntary actions of the body.
Frontal lobe - Controls movement
Parietal lobe -Controls sensory areas.
Temporal - Interprets sound and comprehends language.
Tell me about tut thalamus.
Central brain area - Distributes information to cerebral cortex.
Inform me with knowledge about the Hypothalamus of the brain.
Controls - emotions, drives, regulating temperature and blood pressure.
Situation where sympathetic nervous system would take effect?
Fight or flight.
Btw you can spell ‘neurone’ or ‘neuron’ either way it doesn’t matter.
…..Yeah…that’s correct.
Components of a neurone cell?
Dendrites Nucleus Cell body Axon Axon terminal Myelin sheath Schwann cell Node of Ranvier.
For Neurone cell structure >
https://www.dreamstime.com/royalty-free-stock-photos-structure-typical-neuron-anatomy-human-axon-synapse-dendrite-mitochondrion-myelin-sheath-node-ranvier-schwann-cell-vector-image35116978
Three types of neurones? What do they connect?
Sensory neurone: Receptor > CNS
Relay neurone: CNS > CNS
Motor neurone: CNS > Effector
Difference between Dendrites and Axons in terms of impulse direction?
Dendrites - Carry nerve impulses towards cell body.
Axons - Carry nerve impulses away from the cell body.
Schwann cell function?
Wrap around axon multiple times to protect axon and for electrical insulation.
What is the Myelin sheath and what does it act as?
Membrane of Schwann cells that acts as axon covering.
Rich in myelin lipid
Nodes of Ranvier?
Gaps in schwann cells where there’s no myelin sheath.
Where does a neurone’s axon meet another neurones dendrites?
The Synapse.
Where are synapses found?
Between neurone’s dendrites and axons. And between axons and other cells. E.g muscle cells (intermuscular junction).
What’s the gap in the synapse between the axon and dendrites called?
The synaptic cleft.
Order of a response?
Stimulus > sensory neurone > relay neurone (can be called interneurone) > motor neurone > Effector > response.
What happens when an action potential reaches the end of an axon?
Neurone releases neurotransmitters by exocytosis into the intercellular space (synaptic cleft). These bind to receptors on the target cell - opens ion channels and if threshold is achieved the target cell generates an action potential.
Some diseases linked to the central nervous system?
- Motor neurone disease.
- Alzeiheimer disease
- Parkinsons disease
- Guillain-Barre syndrome
- Multiple sclerosis
- Drugs (interrupt synaptic transmission)
Know some glands and their functions.
Pituitary - Secretes LDH and other hormones.
Parathyroids - Helps regulate blood calcium levels
Adrenal - Fight or flight response triggering.
Pancreas - Blood sugar level regulation
Testes - Male sex hormones -Testosterone
Ovaries- Female sex hormones - Oestrogen.
What does the endocrine system do?
Senses and reacts appropriately to changes inside and outside the body.
Examples of difference between Endocrine and Exocrine glands?
Exocrine glands - secretes hormones and substances into its own organ or around itself - liver, pancreas, stomach.
Endocrine - secretes hormone into blood to target cells - pituitary , thyroid, adrenal, ovaries, testes.
What does the pineal gland produce?
Melatonin for sleep patterns.
Examples of what the pituitary gland produces and to where?
Growth hormone (GH) - Bones/Muscles. Prolactin (PRL) - Mammary glands. Follicle-Stimulating hormone (FSH) and luteinising hormone (LH) - Testes/Ovaries.
What does the thyroid gland produce and what for?
Produces thyroxine - Effects metabolism, bone growth and blood calcium levels.
Need to apologize. After finishing this I’ve worked out some of these cards are unnecessary so yeah sorry about that.
Sorry lol.
Hey free blue card!!!!
Nice!!
What does the parathyroid gland secrete and what for?
Secretes parathyroid hormone (PTH) - raises blood calcium levels for skeletal development.
Process of negative feedback of calcium homeostasis? When calcium blood levels rise?
- Blood calcium level rises
- Thyroid gland releases calcitonin
- Stimulates calcium deposition in bone and reduces calcium uptake in kidneys.
- Blood calcium levels decline to set point.
Process of negative feedback of calcium homeostasis? When calcium blood levels drop?
- Blood calcium levels drop.
- Parathyroid gland releases PTH
- Stimulates calcium release from bones and calcium uptake in kidneys.
- Also increases calcium uptake in intestines
- Blood calcium levels rise to a set point.
What does the Thymus gland secrete? And what does this make it a part of?
- Secretes Thymomyosin for t cell formation.
- So thymus gland is also part of the immune system.
Adrenal glands?
- Adrenal Cortex produces steroid hormones - more long term stress response.
- Adrenal Medulla produces adrenaline and noradrenaline - responds to immediate fight or flight.
Pancreas?
- a (alpha) cell of islets of Langerhan secrete glucagon.
- b (beta) cells of islets of Langerhan secrete insulin.
Essential for natural blood glucose regulation.
What do Testes produce? Features of what they produce?
- Produces and secretes steroid hormone testosterone.
- Testosterone needed to develop male characteristics e.g hair and muscle growth.
- Testosterone is necessary for healthy sperm production.
Features of Ovaries?
- Produces steroid hormones oestrogen and progesterone.
- Only active after puberty.
- Stimulate female characteristic development.
- Controls menstrual cycle.
Features of the Placenta?
- Produces hcg early in pregnancy.
- Produces oestrogen and progesterone later on in pregnancy.
- Produces human placental lactogen
- Produces relaxin
- Oestrogen and progesterone halt additional ovulation.
What stimulates hormone secretion?
Nervous stimulation - Fight or flight
Hormonal - Exocrine hormone secretion
Humoral - Changed in variables in blood.
What is the essential structure of steroid hormones?
Cholestrol
True or false? Steroid hormones aren’t water soluble.
True. Steroid hormones aren’t water soluble.
Examples of endocrine system disorders?
Diabetes, Hypothyroidism, Hyperthyroidism, low fertility levels.
Process of negative feedback of insulin when blood sugar rises?
- Homeostasis
- B - cells of islets of langarhans in pancreas secrete insulin into blood.
- Liver cells convert glucose to glycogen using insulin
- At same time Body cells become more permeable to glucose.
- Blood glucose level decreases to normal level.
Process of transmission across a synapse?
Sorry this is a doozy
- Action potential arrives at presynaptic neurone - causes calcium ion protein channels to open and calcium ions to enter pre-synaptic neurone.
- Influx of calcium ions causes acetylcholine to be released into synaptic cleft.
- Acetylcholine diffuses across synaptic cleft and binds to receptor sites on sodium ion channel proteins on post synaptic neurone.
- Causes sodium ion channels to open releasing sodium ions to diffuse into the postsynaptic neurone.
- This generates a new action potential
- Sodium ion protein channels close in absence of acetylcholine receptor cells.
Nerve impulses rely of concentration gradients controlled by what?
Transmembrane proteins in the phospholipid bi-layer.
Define membrane potential.
Electric potential across cell membranes maintained by different charged particles on either side of the membrane.
Axon charge difference at resting potential?
Inside of axon is negatively charged relative to outside of the axon. Usually -65mV.
What is the threshold for sodium channels to open at?
-55mV
Define a Nerve impulse?
Self propagating wave of electrical disturbance that travels along the surface of the axon membrane.
What is the axon’s state during resting potential?
Polarised
Process of regulating a resting potential?
Sorry this is a doozy
- Sodium ions being actively transported out of axon by sodium-potassium pump.
- Potassium ions being actively transported into the axon by sodium potassium pump.
(^Potential difference between inside and outside of axon is due to^^^^^^^^^^^^^^^). - Active transport of sodium ions is greater than that of potassium ions - 3Na out for every 2K in.
- Na and K ions are both positive - but movement means more Na in tissue fluid around axon than in cytoplasm and more K in cytoplasm than tissue fluid - so chemical gradient created.
- Na ions diffuse back into axon naturally, K ions diffuse out of axon naturally.
- Most gates allowing k ions to move through were open, most gates allowing Na ions to move through are closed.
- Result - axon more permeable to K ions which diffuse out of axon faster than Na ions in.- Increases potential difference (difference in charge).
- More K ions diffuse out of axon - outside of axon becomes more positive - generates electrical gradient.
- Further movement of K ions out of axon becomes difficult - as they’re attracted to negative state in axon as they are positively charged along with being repelled by positive charge in tissue fluid.
10.Equilibrium of balanced chemical and electrical gradients is established - no net movements of ions.
Action potential?
The energy of the stimulus received by the receptor causes a temporary reverse of charge on the axon membrane -65mV > +30mV
In what condition is the axon during an action potential?
Polarised.
Process of an action potential?
(Sorry this is a doozy),
- At resting potential - some K voltage-gated channels are open - some Na channels are closed.
- Stimulus energy causes Na voltage gated channels to open so Na ions diffuse into electrochemical gradient - they’re positively charged so trigger reversal in potential difference across the membrane.
- Na ions diffuse into axon - triggers more Na channels to open - increases Na influx by diffusion.
- Once action potential of roughly +3mV is established - voltage gates for Na ions close and K voltage gates open.
- Some K voltage gated channels open - electrical gradient preventing outward flux of K is reversed - more K channels open - make k ions diffuse out - This REPOLARISES the axon
6, Outward movement of K ions causes temporary overshoot of electrical gradient - Inside of axon more negative to outside than usual - HYPERPOLARISATION. - Gates on K channels close - sodium-potassium pump once again causes Na to be pumped out and K to be pumped in.
- RESTING POTENTIAL - 65mVis re-established - axon has been REPOLARISED.
How does the impulse move along the axon?
- Wave of depolarisation continues along membrane
- Ion pumps then re-establish normal resting potential.
How long does the refractory period last?
As long as it takes to return to the resting potential.
What is the refractory period?
Time where it’s impossible for a further action potential to be generated in the neurone.
Which type of neurone transmits impulses faster and why?
Mylinated neurones transmit nerve impulses faster.
The ‘impulse’ leaps from one node to the next, which greatly speeds up the journey of the impulse along the axon. Because myelin sheath conducts the impulse to each node of Ranvier instead of generating an action potential each time. so its quicker.
Define the process of the impulse being conducted by a myelinated neurone?
Saltatory conduction.
Fun fact. ‘Saltus’ is the Latin word for ‘to leap’
