NS & ES Flashcards
Function of cerebral cortex (grey matter)
Conscious thought & awareness of stimuli
Describe pathway of sensory info.
Receptor -> Sensory neuron -> ascending/sensory tracks in SC -> brain stem -> Thalamus -> cerebral cortex
Describe pathway for sensory info.
Receptor -> Sensory neuron -> ascending/sensory tracks in SC -> brain stem -> Thalamus -> Cerebral cortex (integration & awareness of stimuli)
Describe pathway for motor info.
Cerebral cortex -> impulses for consious decision travel through cerebrum -> brainstem -> motor/descending tracts in SC -> synapse to motor/effterent neuron -> efffector organ
Define reflex
Rapid (min. synapse), Involuntary, Predictable (same), Unlearnt (reflex arc) response to a stimulus. Bypass conscious part of brain => rapid resp.
Path of reflex arc
- Sensory receptor
- Sensory neuron travel through nerve & dorsal root ganglion
- Interneuron = Integration area
- Motor neuron travels through ventral root
- effector organ
Somatic reflex & e.g.
- Effector: skeletal muscles
- Function: Prevent further damage from stimuli; balance/posture
- Integration: SC or brain
- E.g: Patellar reflex
Autonomic reflex & e.g
- Effector: Smooth muscle, cardiac muscle, body viscera (salivary glands, gut wall)
- Function: maintain bodily functions (move food through digestive sys, HR, BP, CO2 levels)
- Integration: SC or brainstem through Autonomic NS
- E.g: Defecation & micturition reflex
Briefly describe diff. b/w sub & conscious control
Sub: No decision making (less synapse); not complicated (quick resp.)
Conscious: Decision making (more); complicated resp (slow)
Diff. b/w NS & endocrine
NS: rapid resp. (AP & neurotrans.), Sub/conscious control
ES: Slow resp. (hormones in blood), feedback loops
Function of medulla oblongata
Integrate reflexes (many nuclei/grey matter)
- Respiratory (Medullary rhythmicity center)
- blood vessel (vasomotor center)
- HR (cardiac center)
- swallowing, coughing, vomiting, hiccuping
Function of pons
(Nuclei)
- Sleep centre initiates REM (deep) sleep
- respiratory (Pontine respiratory centre)
Function of midbrain
(nuclei stabilise somatic movement)
- VIsual reflexes (head & eye movements tracking objects)
- Auditory reflexes (startle reflex)
what connects pituitary gland to hypothalamus
Anatomically: infundibulum (pituitary stalk)
Functionally: blood vessels & nervous tracts
Functions of hypothalamus
- Homeostatic mechanism: Tb, sleep-wake cycles, food intake, water balance & thirst
- autonomic control: pituitary gland secretions, regulate cardiac & smooth muscle & glands
2 pituitary glands & origin
Ant. (adenohypophysis) 70-80%: made of glandular cells from roof of mouth
Post. (neurohypophysis): made of neural tissue. Grew down from brain
Name of network of capillaries in Ant. Pt gland, & the tract in the Post Pt gland
Ant: hypothalamohypophysial PORTAL system
Post: hypothalamohypophysial TRACT (allow neural secretion= release hormones)
Tropic hormones & e.g
Secreted from one gland to stimulate another endocrine gland. E.g. FSH, LH, TSH, ACTH
Types of communication: Differentiate autocrine, paracrine & endocrine cells
Auto: affects same cells that secrete chemicals
Para: affects local cells
Endo: affects (target) cells distant from source
Diff. Endocrine & exocrine glands
Endo: ductless. Hormones diffuse into interstitial fluid into capillaries
Exo: ducts seccrete products (not hormones)
2 types of hormones & e.g.
- AA based = water soluble. E.g. all from Pt gland
- steroid based = lipid soluble. E.g. hormones w/ -one
* Thyroxine (T3 & T4) is AA but is LIPID soluble
Describe transport w/water & lipid soluble
Water: dissolve in plasma & travel freely. Degrade rapidly
Lipid: combine w/ binding protein when in blood but released when going out
Method of action for direct method
- lipid soluble H diffuse in cell through membrane
- attach to receptor inside cell (cytop. / nucleus)
- Hormone-receptor complex travel to nucleus (nuclear envelop)
- Activates specific genes (=> protein synthesis)
3 ways hormones alter cell activity
- Change activity of organelles
- Change cell membrane permeability
- Activate a cell mechanism
Method of action for indirect method
- water soluble H attach to receptor on membrane’s surface activate G protein complex (alter activity of adenyl-cyclase)
- Enzyme converts ATP -> cAMP (2nd messenger).
- Protein-kinases (regulatory enzyme) activated
- Cell processes altered (e.g. activate enzymes)
HUMORAL stimuli for hormone release
Changing blood levels (substances in blood) as the stimulus. E.g. parathyroid gland secreted if low Ca2+
NEURAL stimuli for hormone release
Neurotrans. (released from nerves) stimulate target cell (to release hormones). E.g. adrenal medulla stimulated by parasym. NS
HORMONAL stimuli for hormone release
(tropic) hormones stimulate target cells to secrete hormones
Diff. b/w -ve & +ve FB
-ve: reduce stimulus
+ve reinforces stimulus
6 Major endocrine glands
hypothalamus, Pt gland, Thyroid & parathyroid gland, adrenal gland & pancreas
Pancreatic islets produce # hormones which are and each produced by _ cells…
3.
> Glucagon (alpha)
> insulin (beta)
> Somatastatin (delta)
