ME03 - Higher Cortical Functions Flashcards
Portion of anterior end of diencephalon that lies below the hypothalamic sulcus and in front of the interpeduncular nuclei
Divided into a variety of nuclei and nuclear areas
Hypothalamus - links the nervous system to the endocrine system via the pituitary gland
Important Functions of the Hypothalamus
ENDOCRINE FUNCTIONS
AUTONOMIC FUNCTIONS
LIMBIC FUNCTIONS
What are the Endocrine Functions of the Hypothalamus
Cardiovascular regulation_- involves control of blood pressure and heart rate
Body temperature regulation hypothalamus signal appropriate cells to activate body temperature-lowering or temperature-elevating mechanisms
Regulation of body water intake (thirst)- controls urinary excretion of water
Uterine Contraction and Milk Ejection - causes contraction of the smooth muscle of the uterus and milk let down
Gastrointestinal and feeding regulation
Anterior pituitary gland regulation
Increase BP and HR
Posterior and Lateral hypothalamus
Decreases BP and HR
Preoptic Area
Cardiovascular Regulation is mediated by
Cardiovascular centers in pontine and medullary reticular formation
Controls the set-point of human body temperature
Hypothalamus
Controls the body temperature regulation
Neurons in the preoptic area
What is the thirst center?
Lateral hypothalamus
Release antidiuretic hormone (ADH) into posterior pituitary
Magnocellular cells in supraoptic nuclei
In Uterine Contraction and Milk Ejection, this is responsible for the release of oxytocin
Magnocellular cells in paraventricular nuclei
MNEMONICS Paraventricular nuclei
Oxytocin = Para sa Voobs
What is responsible for hunger?
Lateral hypothalamus
Lesion in the lateral hypothalamus results to:
Starvation
What inhibits the Lateral Hypothalamus?
Leptin
This is the satiety center | activity produces a stop eating signal
Ventromedial nucleus
Lesion in the Ventromedial nucleus results to:
Uncontrolled vo- racious appetite
What stimulates the Ventromedial nucleus?
Leptin
Involved in re- flexes related to food intake like lip licking and swallowing
Mamillary nuclei
Responsible for the releasing and inhibitory factors that modulate anterior pituitary function
Periventricular zone, Arcuate nucleus and Ventromedial nucleus
“Head Ganglion” of autonomic nervous system
Autonomic Functions of the Hypothalamus
Stimulation of the hypothalamus produces autonomic responses. True or False?
True.
What are the different autonomic functions of the Hypothalamus
Sympathetic: posterior hypothalamus»_space; has a warming function
Parasympathetic: anterior hypothalamus»_space; has a cooling function
Stimulation of hypothalamus affects behavioral control functions
Limbic Functions of the Hypothalamus
Causes increased general level of activity leading to rage and aggression
Lateral hypothalamus
Causes sense of tranquility, pleasure and reward
Ventromedial nucleus
Evokes fear and feel- ings of punishment and aversion
Periventricular nuclei
Sexual Arousal is stimulated from what portion of the hypothalamus?
From most anterior and most posterior portions of the hypothalamus
What are the Types of Biologic Periodicity
Ultradian Rhythms | Infradian Rhythms | Circadian Rhythms
Cycles of periodicity shorter than 24 hours
Ultradian Rhythms | Ex: heart beat, respiratory rhythm
Cycles of periodicity longer than 24 hours
INFRADIAN RHYTHMS | Ex: menstrual cycle, gestation
Cycles of periodicity that approximate Earth’s rotational period (24-hour day)
Circadian Rhythms | Ex: Sleep-Wake cycle, Hormone levels
Regulate activity of many physiological processes including heart rate, blood pressure, body core temperature and blood levels of hormones
Biologic Clock
External environmental clues influence strict 24- hour cycles. True or False
True.
Master clock of all biological clocks in the human body
Suprachiasmatic Nucleus
Function of SCN
Retain synchronized, rhythmical firing patterns even though they are isolated from the rest of the brain
Destruction of SCN will cause
Loss of circadian functions
Implicated in regulation of circadian rhythms
Pineal Gland
A hormone that is synthesized from serotonin; which is responsible for:
o increased during darkness
o inhibited by daylight
o controlled by sympathetic nerve activity, which is regulated by light signals from the retina
Melatonin
Also known as jet lag
Physiological condition which results from alterations of circadian rhythms
Desynchrosis
Reason behind when traveling across time zones, body clocks will
be out of synchronization with the destination time
Due to experience of daylight and darkness contrary to accustomed
rhythms
How do you treat Jet Lag/Desynchrosis?
Treated with melatonin or sunlight exposure
Unconsciousness from which the person can be aroused by sensory or other stimuli
Sleep
Distinguish coma from sleep?
Coma is unconsciousness from which the person cannot be aroused
2 Types of Sleep
Slow Wave/Non REM Sleep | REM Sleep
Describe Slow Wave Sleep/Non REM Sleep
o deep, restful type of sleep
o characterized by decreases in periph- eral vascular tone, blood pressure, respiratory rate and metabolic rate
o frequently called dreamless sleep
o however, dreams and sometimes even nightmares do occur during slow-wave sleep
Why is REM called the “Paradoxical Sleep”?
Because the brain is active and skeletal muscle con- tractions occur
Describe Rapid Eye Movement (REM) Sleep
active form of sleep associated with dreaming and active bodily muscle movements
o lasts 5 to 30 minutes
o repeats at 90 minute intervals
o may be absent in extremely tired individuals
REM is more difficult to arouse than slow-wave sleep. True or False?
True.
What are some of the Important Characteristics of REM sleep
Muscle tone is exceedingly depressed
irregular heart rate and respiratory rate (dream state)
irregular muscle movements do occur
brain is highly active in REM sleep
What are the sleep centers in a Slow-Wave Sleep?
raphe nuclei in lower pons and medulla
nucleus of the tractus solitarius
diencephalon
o rostral hypothalamus (suprachiasmal area)
o diffuse nuclei of thalamus
Most conspicuous stimulation area for causing almost natural sleep
Raphe nuclei in lower pons and medulla (SLOW-WAVE SLEEP)
What neurotransmitter is elaborated from raphe nuclei?
Serotonin