Control of body systems Flashcards
What is the function of the nervous system?
Receive sensory inputs, integrate information and produce and appropriate response
What response do sympathetic nerves produce?
Fight or flight response
Which number spinal nerves are sympathetic?
T1-L2
Where are sympathetic nerves ganglia located?
In paravertebral or prevertebral ganglia in the sympathetic chain
Where are the different sympathetic chain regions located?
Paravertebral- thoracic and lumbar spine
Prevertebral- clustered around the anterior aorta
What nervous system is responsible for rest and digest?
Parasympathetic
Which nerves are parasympatetic?
Cranial- 3, 7, 9, 10
Spinal- sacral spinal nerves
Where are ganglia located for parasympathetic nerves?
Close or within target organ
Which cranial nerves are sensory?
I
II
VIII
Which cranial nerves are motor?
III IV VI XI XII
Which cranial nerves are both sensory and motor?
V
VII
IX
X
What is cranial nerve I and what is its role?
Olfactory
Smell
Which cranial nerve is optic and what is its role?
II
Vision
What is cranial nerve III and what is its role?
Oculomotor
Eye movement
What is cranial nerve IV and what is it responsible for?
Trochlear
Eye movement
Which cranial nerve is responsible for sensation and mastication and which number is it?
Trigeminal
V
What is cranial nerve VI and what is its role?
Abducens
Eye movement
Which cranial nerve is the facial nerve and what is its role?
VII
Facial expression and taste
What cranial nerve is responsible for balance and hearing and what number is it?
Vestibulocochlear
VIII
What is cranial nerve IX and what does it do?
Glossopharyngeal
Taste, gag reflex
Which cranial nerve is the vagus nerve and what is it responsible for?
X
Soft palette, pharynx, larynx, and parasympathetics to thorax and abdomen
What cranial nerve is responsible for shoulder shrug and what number is it?
Accessory
XI
What is cranial nerve XII and what does it do?
Hypoglossal
Tongue movement
What are upper motor neurones?
Fully in CNS, cell bodies in cerebral cortex.
Initiate voluntary movement
Maintain muscle tone and posture
What do lower motor neurones do?
Innervate skeletal muscle via cranial or spinal nerves
What do descending tracts do?
Carry motor signals from the brain to lower motor neurones causing voluntary limb control and involuntary head movement, posture and balance
What is the pyramidal system responsible for?
Complex learned voluntary movement, fine motor control from medullary pyramids
What is the role of the extrapyramidal system?
Maintain posture, rhythmical activity (eg. locomotion) and semi-automatic processes (eg. feeding)
Which nerves are responsible for prehension?
Facial
Hypoglossal
Which nerve is responsible for mastication?
Trigeminal
How do facial and hypoglossal cranial nerves lead to slaviation?
Cause parasympathetic supply to salivary glands initiated by tactile stimulus in mouth, taste, food thoughts and hunger
How do the enteric nervous system plexi regulate digestion?
Myenteric plexus- motility and muscle action
Submucosal plexus- regulate fluid and hormone release
What nerves are involved in the gag reflex?
Glossopharyngeal nerve picks up the sensation of food
Vagus nerve causes the action to prevent food entering the pharynx
How are gastric secretions regulated?
Cephalic phase causes vagus nerve to act on stomach increasing secretions and releasing hormones
The hormones have positive feedback on increasing secretions
Stomach distention increases vagus stimulation further increasing secretions
How is bile secretion initiated?
Chyme in duodenum stimulates hormone release
Hormones and vagus nerve cause bile secretions and gall bladder contraction
How does stomach distension and chyme in duodenum lead to defecation?
Stimulates movement of contents to rectum
Faeces distend rectum causing increased colon and rectal contractions
Local reflexes act on internal anal sphincter
Sensory signals get sent via pelvic nerve and descending tracts regulate defecation reflex
Pudendal nerve acts on external anal sphincter
What nerve innervates to external urinary sphincter?
Pudendal nerve
How does a musculocavernous penis become errect?
Thoughts or stimulation sends signals to sacral spinal cord
Parasympathetic nerves vasodilate arteries in erectile bodies and veins compress so blood flow out is reduced
How does a fibroelastic penis become errect?
Decreased sympathetic tone casues relaxation of smooth muscle allowing sigmoid flexure to straighten
How is hormone release initiated?
Metabolites, neuronal and hormonal stimuli
How is hormone release regulated?
Inhibitory and excitatory feedback mechanisms
What connects the pituitary gland to the hypothalamus?
Infundidium
Which part of the pituitary gland is neuronal and which part is hormonal
Posterior- neuronal
Anterior- hormonal
How does the posterior pituitary release hormones?
Stimuli increases/decreases action potentials in hypothalamic neurones
Action potentials travel to posterior pituitary
Hormones in axon terminals get released into bloodstream
What are examples of hormones released by the pituitary gland?
Posterior- ADH , oxytocin
Anterior- LH, FSH, thryroid stimulating hormone
How does the anterior pituitary release hormones?
Hypothalmic neurone release inhibitory/releasing hormones
Hormones flow in blood to anterior pituitary
Hormones pass into pituitary cells to stimulate/inhibit hormone release into the blood
What are the different cells present in the testes roles?
Leydig cells- secrete testosterone
Sertoli cells- support developing germ cell
Germ cell- mature as reach the lumen
What is the structure of the thyroid?
2 lobes connected by isthmus Highly vascular Walls are follicular cells/simple cuboidal epithelium Filled with thyroglobulin Parafollicular cells between follicles
What do the different cells in the thyroid release?
Follicular cells- T3 and T4
Parafollicular cells- calcatonin
Where is the thymus?
Neck and superior thorax
What is the role of the thymus?
Release thymosin
Immune development
What is the role of the pineal gland?
Produce and release melatonin to control sleep cycles and seasonal breeding by affecting LH and FSH release
How is melatonin release regulated?
Light enters eye stimulating hypothalamus
Impulses sent to pineal via sympathetic nerves
More light causes less impulses and less melatonin production
Where are parathyroid glands?
4 on posterior surface of thyroid gland
What do parathyroid glands do?
Secrete parathyroid hormone to increase Ca2+ into blood
What do the different adrenal gland regions release?
Cortex- steroid hormones
Medulla- adrenaline and noradrenaline
What do the different types of pancreas release?
Endocrine- digestive hormones
Exocrine- digestive enzymes secreted by acini cells
What observations about muscles can be used to predict their actions?
Origin
insertion
Joint muscle crosses
Muscle fibre direction
What action does the anterior compartment of upper arm have?
Elbow flexors
What action does the anterior compartment of the forearm have?
Carpal and digit flexors
What action does the posterior compartment of the upper arm have?
Elbow extensors
What action does the posterior compartment of the forearm have?
Carpal and digit extensors
What action does the anterior compartment of the thigh have?
Knee externsor
What action does the medial compartment of the thigh have?
Thigh adductor
What action does the posterior compartment of the thigh have?
Knee flexor
What action does the anterior compartment of the lower leg have?
Dorsiflex ankle and extend digits
What action does the posterior compartment of the leg have?
Plantarflex ankle and flex digits
What supplies dermatomes and myotomes?
Somatic spinal nerves
Where does the spinal cord have intumescence and why?
Cervical and lumbosacral regions
Supply limbs so high amounts of inputs and outputs
Name the plexuses that supply the limbs
Brachial- upper limbs
Lumbosacral- lower limbs
What are motor cortices?
Brain and spinal regions C6-T2 that initiate and control movement
(Anterior to posterior) Name the motor cortices regions in the brains and their role
Prefrontal area- motivation and foresight to plan and initiate movement
Premotor area- organise motor function before initiation
Primary motor cortex- initiate and control voluntary movement
Name the roles of the cerebellum
Posture Muscle tone Balance Fine motor coordination Movement modification Planning complex actions
Define basal nuclei
Collection of nerve cell bodies in the brain
What is the role of basal nuclei?
Planning, organising and coordinating movement
Posture
Where are intercostal nerves loctaed?
Between ribs
Explain the role of musculocutaneous nerve
Elbow flexor
Sensory innervation of skin in area
What does the radial nerve innervate?
Elbow extensors
Carpal and digit extensors
What does the median/ulnar nerve innervate?
Carpus and digit flexors
What does the obturator nerve innervate?
Thigh adductor
What does the femoral nerve innervate?
Knee extensor
What movement does the sciatic nerve innervate?
Knee flexor
What does the fibular nerve innervate?
Hock flexor
Digit extensors
What does the tibial nerve innervate?
Hock extensor
Digit flexor
