L3 HOMEOSTASIS and CONTROL and CONTROL SYSTEM Flashcards
What is HOMEOSTASIS?
The maintenance of constant INTERNAL environment
What is negative feedback? describe the process
Brings levels back to normal, eg if levels go too high it decreases it
If too low it increases it.
- Change
- Sensor detects change
- Signals are sent to INTEGRATING SYSTEM
- INTEGRATING SYSTEM transmits impulse to effector
- effector bring change
What are normally the effector cells in the BODY?
Muscle cells, secretory cells
What are the two main integrating system?
CNS, endocrine system
What is afferent pathway?
its the INCOMING pathway, incoming signals
What is efferent pathway?
OUTGOING signals pathway to effector
How is FALL in blood pressure regulated? (Haemorrhage)
- Fall in blood, receptor detected by sensory STRETCH BARORECEPTOR located in the CAROTID ARTERIES
- propel signal through gloss-pharyngeal nerve to
- MEDULLA OBLONGATA
- Which sends impulses to ANS in sympathetic branch
- Heart rate is increased which increases BP
What is POSITIVE FEEDBACK?
its when initial change is change even further instead of being brought back to normal in the case of negative feedback
Give 3 example of positive factor.
- Formation of blood clot
- ovulation
- Action potential
Which integrating system has LONG TERM EFFECTS?
endocrine system
Which integrating system has SHORT term effects?
nervous system
what nerves control the CONSCIOUS skeletal system?
SOMATIC nerves
What system is the unconscious system?
Autonomic nervous system
Where do preganglionic nerves of the SYMPATHETIC nervous system originate?
- Thoracic and Lumbar part of the spine (middle)
Where do preganglionic nerves of the PARASYMPATHETIC system originate from?
Sacral and Cranial part of the spine (top and bottom)
What is the length of Ganglionic nerves in the SYMPATHETIC NS?
- Shorter preganglionic nerves
- Longer Post-ganglionic nerves
What is the length of Ganglionic nerves in the PARASYMPATHETIC nerves?
- Longer pre-ganglion nerves
- Shorter post ganglionic nerves
How does the SYMPHATHETIC nervous system coordinate a response?
Impulse arrives at Preganglionic nerves located in Lumbar and Thoracic region
- impulse transmitted along to post-ganglionic nerves through neurotransmitter ACETYLCHOLINE binding to N2 (nicotinic) receptors on post-ganglion nerves
- Postganglionic nerves propels impulse along using NORADRENALINE which binds to androgenic receptor alpha and beta on effector
- Increase in acitivity
How does the PARASYMPATHETIC nervous system coordinate response?
impulse arrives at preganglionic nerve
- Impulse transmitted along to post-ganglionic nerves through ACH binding to n2 receptor on post-ganglionic nerves
- Postganglionic nerves transmit impulse along to effector also releasing ACH
- which binds to MUSCARINIC receptor on effectors
- Decrease in activity
What can also act as NORADDRENALINE?
Adrenaline
Describe NEGATIVE feedback using a HORMONAL example?
- Cortisol is HIGH in the morning and it need to be brought down
How cortisol is increased: - Hypothalamus releases CRH
- CRH travels to anterior pituarity gland
- which causes the release of ACTH
- ACTH binds to adrenal gland increasing CORTISOLA
How cortisol is decreases;
Process 1 increases cortisol levels
- When it reaches a certain threshold it will be detected by Hypothalamus
- which will stop production of CRH
- Which means no process of increasing cortisol level
Give and describe an example of positive feedback as HORMONAL response
- Lactation
- Baby is suckling
- OXYTOCIN is released
- Oxytocin stimulates contraction of milk duct
- milk is produced
This is an example of positive feedback as when there is change detect which is the baby suckling the response is INCREASED further instead of trying to control it
