Hypothalamus and limbic system

What are the key roles of the hypothalamus?

• Links nervous and endocrine systems

• Regulates autonomic circuits

• Maintains homeostasis (e.g., body temperature, hunger, sleep)

What physiological functions does the hypothalamus regulate?

• Blood pressure and electrolyte composition- hypothalamus regulates thirst, salt appetite and drinking behavior

• Energy metabolism- regulates hunger and feeding behavior, autonomic control of digestion, the release of glucocorticoids, growth hormone and thyroid- stimulating hormone

• Reproductive behaviors- autonomic modulation of reproductive organs and endocrine regulation of gonads

• Body temperature- influences thermoregulatory behavior, controls autonomic body heat conservation/loss mechanisms

• Defensive behavior- regulates the stress response

• Sleep-wake behavior- regulates the sleep-wake cycle and levels of arousal when awake

What is the function of the supraoptic nucleus?

Produces oxytocin, involved in uterine contraction and lactation.

What does the paraventricular nucleus synthesize and control?

Produces vasopressin (ADH) – regulates vasoconstriction and water reabsorption in kidneys.

What is the role of the arcuate nucleus?

Regulates feeding, metabolism, fertility, and cardiovascular function.

What are the roles of these hypothalamic structures?

• Suprachiasmatic nucleus

• Ventromedial hypothalamus

• Mammillary bodies

• Suprachiasmatic nucleus: Sleep-wake (circadian) rhythm

• Ventromedial hypothalamus: Regulates food and fluid intake

• Mammillary bodies: Involved in recollective memory

What is the structural difference between anterior and posterior pituitary?

• Anterior pituitary: Endocrine origin

• Posterior pituitary: Neural origin

Which hormones are released by the hypothalamus to act on the pituitary?

• Oxytocin & vasopressin (posterior)

• GHRH → stimulates GH release (anterior)

• GnRH → stimulates FSH/LH release (anterior)

What are the two divisions of the autonomic nervous system?

• Sympathetic: Fight or flight

• Parasympathetic: Rest and digest

What are the overall functions of the ANS?

• Maintain homeostasis

• Regulate cardiac, smooth muscle, and glands

• Coordinate involuntary functions related to stress, emotion, and metabolism

How does the ANS regulate blood pressure?

• Baroreceptors in carotid sinus detect pressure

• Medulla integrates signals → sympathetic system increases cardiac output and vasoconstriction

• Increases mean arterial pressure

which is afferent and which is efferent

Identify these gyri

Identify the gyri and their locations

straight

parahippocampal

uncus of parrahipocampal

inferior occipital

orbital

occipiatemporal/fusiform

inferior temporal

lingual

Identify these structures

What are the functions of limbic system components?

CPHA

FO

• Cingulate gyrus: Emotion & behavior

• Parahippocampal gyrus: Memory encoding/retrieval

• Hippocampus: Long-term memory and spatial memory

• Amygdala: Emotion, decision-making, emotional memory

• Fornix: Major output of hippocampus

• Olfactory system: Smell

Identify these structures

Identify these structures

What are 4 key functional areas of the temporal lobe and their functions?

EPPF

• Entorhinal cortex: Declarative & spatial memory eg memory formation and consolidation

• Perirhinal cortex: Object recognition, item memory

• Parahippocampal cortex & place area: Scene processing and memory

• Fusiform gyrus: Color processing, face recognition (FFA), linked to synaesthesia and prosopagnosia

Associative agnosia

What it is and what are people unable to do

Can copy or match visual stimuli but cannot see object parts as a unified whole

Unable to construct sensory representations of visual stimuli

Apperceptive agnosia

What it is and what are people unable to do

Cannot interpret understand or assign meaning to objects

sensory representation is created normally but cannot be associative with meaning, function of utility

What are the subdivisions of the hippocampus?

• CA1, CA2, CA3, CA4 (hippocampus proper)

• Dentate gyrus

Identify these structures

Identify these structures

Identify these structures