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