L1: Homeostasis & autonomic nervous system Flashcards
What does homeostasis encapsulate?
-Control of the internal environment
-Maintenance of equilibrium
-Maintenance of variables within limited ranges
-Involves integrated function of different organ systems
What happens is homeostasis is not maintained?
It results in disease (pathophysiology)
Where are changes in light detected in the eye?
Via the ganglia within the retina
What are the different physiological control mechanisms?
Nervous system (ANS or SNS)
Endocrine system (hormones)
Paracrine systems (local control)
What is one of the major functions of the ANS?
To maintain homeostasis
Which nerve fibres control the ANS?
Sensory afferent nerve fibres
What are the control centres of the ANS?
Hypothalamus
Brain stem
Spinal cord
What are the efferent pathways of the ANS?
Sympathetic nervous system and parasympathetic nervous system
What are common features of the efferent pathways of the ANS?
2 neurons in series
Preganglionic neurones (start in CNS)
Postganglionic neurones (start in autonomic ganglia)
1 preganglionic : many postganglionic
What bone compound may have been found to have an important role in fight or flight?
Osteocalcin
What is the preganglionic origin of the parasympathetic nervous system?
Cranial nerve:
III (oculomotor) - eye
VII (facial) - lacrimal, nasal and submandibular
IX (glossopharyngeal) - parotid
X (vagus) - thorax, 2/3 abdomen
Pelvic nerve: rectum & bladder
What is the postganglionic origin of the parasympathetic nervous system?
Ganglia on or near target organ
What are the sizes of the pre and postganglionic nerves in the parasympathetic nervous system?
Pre: long
Post: short
Where is the preganglionic origin of the sympathetic nervous system?
Thoracic 1 (T1) to Lumbar 2/3 (L2/3)
What is the postganglionic origin of the sympathetic nervous system?
2 Paravertebral sympathetic chains
