4.2 Flashcards
Structures of the limbic system
Hippocampal formation
Amygdala
Largely a temporal lobe structure
Hippocampal formation
Involved in the consolidation of short-term memory into long-term memory, learning, and the regulation of aggressive behavior
Amygdala
Regulate emotional expression via modulation of the hypothalamus
Functions of the limbic system
Species preservation: reproduction and instinctive behavior
Self-preservation: feeding behavior and aggression
Expression of fear, motivation, and other motions as well as memory and learning
Often works through the hypothalamus
The limbic system influences movement via the
reticular formation and basal nuclei
Reticular formation prepares for
flight or escape
limbic structures –> hypothalamus –> reticular formation –> spinal cord –> movement
Reticulospinal tracts are responsible for what
Reflexes of the trunk (axial) muscles and limbs
Maintaining posture and balance
The basal nuclei are responsible for
Limbic loop: motivational and emotional aspects of movement
- seems to be involved in sympathetic response
- impulse control
Facial expressions and emotionally charged body movement.
Limbic system inputs to endocrine, autonomic, and somatic motor systems
The limbic system via its extensive and widespread projections influences the endocrine, autonomic and somatic motor systems to produce physiological responses in tissue and organs throughout the body that are appropriate for and accompany a particular emotional situation.
What kind of disease is Alzheimer disease?
A degenerative disorder of the brain and is the most common form of progressive dementia in the elderly. Individuals are unable to form new memories.
What are the functions of the hypothalamus
Maintain homeostasis
- appetite
- fluid/electrolyte balance
- glucose balance
- metabolism
- sleep
- body temperature
What is the hypothalamus?
Part of the diencephalon, below the thalamus (ADD PIC)
Only weighs 4g and is less than 1% of brain weights, but is crucial for life functions.
Hypothalamic afferents
Limbic system
Sensory pathways: ALS
Thalamus
Reticular formation
Endocrine
Hypothalamic efferents
ANS
Endocrine
Hypothalamic control of the ANS: Parasympathetic
Constricts pupils
Increased salivation for digestion
Decreased heart rate and blood pressure
Bladder contraction
Hypothalamic control of the ANS: Sympathetic
Dilate pupils
Decreased salivation
Increased heart rate/ blood pressure
Bladder relaxation
Hypothalamohypophyseal connections
The hypothalamus exerts hormonal control through the pituitary gland, which is really two separate glands: anterior and posterior
Posterior pituitary hormones
ADH - water balance
Oxytocin - childbirth, “cuddle”
Anterior pituitary hormones
CRH stimulated ACTH release: adrenal hormones
TRH stimulate TSH release: thyroid hormones
GnRH stimulates LH/FSH release: gonads
GHRH stimulate growth hormone relase: liver
What is stress?
A physical and emotional reaction that people experience as they encounter life changes.
Acute phase stress response
- Limbic system/amygdala
- Hypothalamus releases CRH
- Anterior pituitary released ACTH
- ACTH triggers cortisol release into the adrenal gland
If stress stimulus persists, chronic cortisol release creates adverse response.
Stress disorder
Acute stress disorder: immediate to 4 weeks
PTSD: >1 month
Chronic stress
ASD and PTSD
The person experiences, witness, or was confronted with an even that involved actual or threatened death or serious injury.
The person’s response involved intense fear, helplessness, or horror.
After an event up to 100% of those exposed show signs, but actual diagnosis is much lower.
Risk factors of ASD and PTSD
Lack of education
Previous trauma
Childhood adversity
Child abuse
Family psychiatric history
Prior psychological difficulties
Trauma severity
Lack of social support following the event
Subsequent life stress
Factors that predict successful coping with stress
Hardiness
- i can have a positive impact
- i have commitment and purpose
- i can learn from the good and the bad
Self-enhancement (positive self image)
Positive emotion
Chronic stress
Immunosuppression
Cardiovascular events
Neurologic sequale: stroke, balanaced d/o
Multiple medical conditions worsen (GI, arthritis, pulmonary)
Morbidity
the condition of suffering from a disease or medical condition
Negative interactions with healthcare providers may lead to:
Delaying or not seeking testing and healthcare
Poorer quality of care received
Poor adherence to treatment regimens
Increased symptoms
Depression
Decreased quality of life
The limbic system helps to produce a physiologic response appropriate for what type of situation?
emotional
The hypothalamus operates largely through its influence on which gland?
pituitary
