Module 1 - Body Control Flashcards
what is the speed and control mechanisms of the nervous and endocrine systems
nervous is rapid and control is conscious or subconscious (somatic or autonomic)
endocrine is slower/prolonged and controlled by feedback loops
what are the 4 major structures (areas) of the brain
- cerebrum
- diencephalon
- brainstem
- cerebellum
what is the cerebral cortex made of, and what is it responsible for
- responsible for conscious thought and recognition of stimulus
- it is made of 2-4mm of grey matter
- and white matter that contains tracts and connects areas
what would be the pathway for sensory information that becomes a conscious recognition
receptor - afferent nerves - ascending tracts in spinal cord - ascending tracts in brainstem - thalamus - cerebral cortex (for conscious thought)
what would be the pathway for motor info (in response to a recognition of sensory info)
cerebral cortex (decision) - descending tracts in brainstem - spinal cord - motor neuron - effector organ
what are 5 characteristics of a reflex
involuntary, rapid (because of minimal synapses), predictable/ stereotyped, unlearnt, doesn’t involve higher brain
what are the 2 types of reflexes and what do they do
somatic - controls skeletal muscles - remove you from pain stimuli, keep balance/posture - involves SC or brain for integration
autonomic - controls smooth and cardiac muscle, and body viscera - maintains body functions - can involve SC and brain stem (eg. for HR and BP)
what are the 3 characteristics of the brainstem and what are its 3 parts
- it is the primitive part of the brain
- it has important integration sections
- all info (higher brain - sc) travels through this region
Parts: Medulla oblongata, pons, midbrain
what is in the white matter of the brainstem
ascending and descending tracts
what is the role of the medulla oblongata (hint: cssvh)
- integration of reflexes
- regulation of heart rate ( cardiac centre)
- regulates blood vessel diameter (vasomotor centre)
- respiration (medullary rhythmicity centre)
- coughing, sneezing, swallowing, vomiting, hiccuping
what is the role of the Pons
- initiates REM sleep (sleep centre)
- respiration (pontine respiratory centre)
what are the 2 centres that work together to aid in respiration and where are they found
- medullary rhythmicity centre ( in the medulla oblongata)
- pontine respiratory centre (in the pons)
What are the roles of the midbrain
- visual reflexes - coordination of head and eye movement (to track moving objects)
- auditory reflexes (startle reflex - when hearing a bnag you look to see where it came from)
what 3 structures make up the wall of the 3rd ventricle
thalamus, subthalamus, hypothalamus
what is the role of the thalamus
relay of sensory info (directs it to specific area)
what is the role of the epithalamus
regulates emotion and circadian rhythm (24hour cycle) - includes the pineal gland
what is the MAIN role of the hypothalamus
homeostasis
what is the role of the subthalamus
controls motor functions
what are the anatomical and functional connections of the hypothalamus and the pineal gland
anatomical connection - infundibulum
functional connection - blood vessels and nervous tracts
what homeostatic mechanisms are controlled by the hypothalamus
- body temp
- sleep wake cycle
- food intake regulation
- water balance and thirst
- autonomic controls - cardiac + smooth muscle + glands and regulates pituitary gland
what type of tissue is the pituitary gland and where did it grow from
the anterior pituitary is glandular tissue and grew up from the roof of the mouth, the posterior pituitary is nervous tissue and grew down from the brain
what % of the pituitary is Anterior pituitary and what hormones does it produce
70-80%
- Growth
- Prolactin
- Melanocyte-stimulating
- thyroid stimulation
- ACTH
- FSH and LH
which of the hormones secreted by the anterior pituitary are tropic and what does this mean
- TSH, ACTH, FSH and LH - the target tissue is another endocrine gland
what is the target for FSH and LH
ovaries and testes
what % of the pituitary is Posterior pituitary and what hormones does it produce
20-30%
- oxytocin
- Antidiuretic hormone
what is a gland
a group of secretory cells
what are the types of communication by hormones secreted by glands (who can they effect)
autocrine - affect themselves
paracrine - affect nearby cells
endocrine - affect cells distant to the source
what type of glands are ductless and what is their mode of transport
endocrine glands
- they secrete chemicals into the interstitial fluid which then diffuses into capillaries and travels in the blood
describe the 2 hormone classifications
AMINO ACID based - made from amino acids, peptides, proteins. (eg. all hormones from the pituitary). they are WATER SOLUBLE and DEGRADE RAPIDLY.
STEROID based - made from cholesterol or fatty acids. (eg. testosterone and aldosterone). they are LIPID SOLUBLE and must combine with binding proteins to travel in the blood
what are the 3 ways that hormone can alter cell activity
- changing organelle activity
- changing cell permeability
- activating a particular cell mechanism (eg. increase or decrease production)
describe the process of water based hormone action
- hormone attaches to receptor on cell membrane
- G Protein is stimulated
- G protein activates (or inhibits) the enzyme Adenyl-cyclase
- Adenyl-cyclase converts ATP into cAMP
- cAMP activates protein kinases
- kinases alter cell processes to produce desired outcome
- cAMP degrades rapidly + effect stops
NOTE:
* Adenyl-cyclase is an enzyme that catalyses the ATP - cAMP reaction
* AMP is the Secondary Messenger
*cAMP is cyclic amine monophosphate
* kinases are regulatory enzymes that alter cell processes
what 3 methods (stimuli) regulate hormones
Humoral Stimuli - direct response to changing levels within the blood (eg. parathyroid gland)
Neural Stimuli - nerves directly stimulate the target cell (eg. adrenal medulla stimulated by sympathetic Nerves)
Hormonal Stimuli - stimulated by tropic hormones from other glands (eg. TSH stimulates thyroid to produce T3+T4)
What are the types of feedback loops
Negative - most common- decreases the effects of the stimuli
Positive - less common - increases the effects of the stimuli
What are the different processes of Direct and INdirect Negative feedback loops
Direct: High levels of hormone X - release hormone Y to reduce levels of Hormone X
Indirect: High levels of hormone X - release of Hormone X inhibiting factor - decrease of Hormone X
what important role does the respiratory centre in the PONS have in respiration
switching between inspiration and expiration
what is the target tissue/gland for Prolactin
Mammary glands AND ovaries
What is the target tissue/gland for FSH and LH
ovaries AND testes
what are the 3 regions of the thyroid gland (in order from right to left)
- right lobe
- isthmus
- left lobe
describe the histology of the thyroid gland
- made up of thyroid follicles (large spherical structures)
- simple cuboidal cells called follicular cells lines the outside of the follicle
- inside is a protein suspension called thyroglobulin
- thyroglobulin contains the hormones to be released
- between the follicles are blood vessels and Parafollicular cells
what is secreted by parafollicular cells and what is it’s function
calcitonin - ↓ Blood Ca++ by promoting Ca++ deposition in bone & ↑ renal Ca++ excretion
describe where parathyroid glands can be found, what they secrete, and what the hormone does
- there are 4 pea shaped structures located on the POSTERIOR side of the thyroid gland
- they secrete parathyroid hormone
- parathyroid hormone increases calcium levels in the blood
how does parathyroid hormone increase blood calcium levels
- promoting Ca++ release from bones
- by decreasing Ca++ excretion
- increasing active Vitamin D levels to increase Ca++ absorption in the GI tract
how does aldosterone retain water
it causes kidneys to retain Na+ and then water follows by osmosis
cortisol can increase the blood levels of what substance
glucose (for energy)
what 2 hormones are secreted by the adrenal medulla
- epinephrine/adrenaline
norepinephrine/noradrenaline
how long is the pancreas and what are the 3 sections
approx. 12.5 to 15 cm
- head, body, tail
describe the endocrine and exocrine functions of the pancreas
- endocrine : secretes insulin and glucagon into the cardiovascular system (bloodstream)
- exocrine : uses a duct to secrete digestive enzymes into a body cavity (exo) - duodenum
