Hypothalamus
1. Lateral nucleus: Hunger center inhibited by _______ Damage leads to ___________ and ____________.
1. Lateral nucleus: Hunger center inhibited by Leptin Damage leads to Anorexia and Aphagia.
Biological actions of GH. The effects on __________ growth, ________ size, and lean body mass are at least partly mediated by insulin-like growth factors (IGFs) (somatomedins) produced in the _______ and in the ___ target tissues as well. ___________, insulin-like growth factor-binding protein.
Biological actions of GH. The effects on linear growth, organ size, and lean body mass are at least partly mediated by insulin-like growth factors (IGFs) (somatomedins) produced in the liver and in the GH target tissues as well. IGFBP, insulin-like growth factor-binding protein.
Dopaminergic neurons and nuclei in the brainstem and rostral projections Substantia nigra (pars compacta) - rostral axons project to _________ and ____________ (_________________ pathway) Ventral tegmental area - rostral axons join _________ ___________ _________ in lateral hypothalamus and project to _________ ___________ (3) and __________ cortex (motor and limbic)
Dopaminergic neurons and nuclei in the brainstem and rostral projections Substantia nigra (pars compacta) - rostral axons project to caudate and putamen (nigrostriatal pathway) Ventral tegmental area - rostral axons join medial forebrain bundle in lateral hypothalamus and project to limbic structures (amygdala, septal nuclei, ventral striatum) and cerebral cortex (motor and limbic)
Feedback Control of Hormone Secretion Negative Feedback Prevents ________________ of Hormone Systems. Although the plasma concentrations of many hormones ____________ in response to various stimuli that occur throughout the day Surges of Hormones Can Occur with _________ Feedback. In a few instances, positive feedback occurs when the biological action of the hormone causes ___________ ___________ of the hormone.
Feedback Control of Hormone Secretion Negative Feedback Prevents Overactivity of Hormone Systems. Although the plasma concentrations of many hormones fluctuate in response to various stimuli that occur throughout the day Surges of Hormones Can Occur with Positive Feedback. In a few instances, positive feedback occurs when the biological action of the hormone causes additional secretion of the hormone.
Stria Terminalis Important path arises from the _________ _____________ and the _______________ cortex projects to the ____ nucleus of the stria terminalis and much of the ___________________ extent of the ________ hypothalamus __________ behavior
Stria Terminalis Important path arises from the medial amygdala and the periamygdalar cortex projects to the bed nucleus of the stria terminalis and much of the rostro-caudal extent of the medial hypothalamus Emotional behavior
Noradrenergic neurons and nuclei in the brainstem and their projections Locus ceruleus - rostral axons join ________ ________ ________ in ________ _____________ and project to most areas of cerebral cortex (3)
Noradrenergic neurons and nuclei in the brainstem and their projections Locus ceruleus - rostral axons join medial forebrain bundle in lateral hypothalamus and project to most areas of cerebral cortex Solitarius Nuc, Dorsal Motor Nuc of X, Reticular formation
"Alarm" or "Stress" Response of the Sympathetic Nervous System When large portions of the sympathetic nervous system discharge at the same time - that is, a mass discharge - this increases in many ways the ability of the body to perform ______________ muscle activity. ______________ arterial pressure _______________ blood flow to active muscles concurrent with decreased blood flow to organs such as the _______________ _______ and the ___________ that are not needed for ________ _______ activity Increased rates of ___________ __________ throughout the body __________ blood glucose concentration ___________ glycolysis in the liver and in muscle ___________ muscle strength ____________ mental activity Increased rate of blood ________________
"Alarm" or "Stress" Response of the Sympathetic Nervous System When large portions of the sympathetic nervous system discharge at the same time - that is, a mass discharge - this increases in many ways the ability of the body to perform vigorous muscle activity. Increased arterial pressure Increased blood flow to active muscles concurrent with decreased blood flow to organs such as the gastrointestinal tract and the kidneys that are not needed for rapid motor activity Increased rates of cellular metabolism throughout the body Increased blood glucose concentration Increased glycolysis in the liver and in muscle Increased muscle strength Increased mental activity Increased rate of blood coagulation
2. Ventromedial nucleus (VMN): __________ center stimulated by ________ Damage leads to _____________ and ________.
2. Ventromedial nucleus (VMN): Satiety center stimulated by Leptin Damage leads to Hyperphagia and Obesity.
3. Anterior hypothalamus: _________ center which senses elevated body temperature and mediates response to dissipate heat via _______________ input. Damage leads to __________________.
3. Anterior hypothalamus: Cooling center which senses elevated body temperature and mediates response to dissipate heat via parasympathetic input. Damage leads to Hyperthermia.
4. Posterior hypothalamus: Heating center which senses _______________ body temperature and mediates the conservation of heat via sympathetic input. Damage leads to _______________ (inability to regulate temperature).
4. Posterior hypothalamus: Heating center which senses decreased body temperature and mediates the conservation of heat via sympathetic input. Damage leads to Poikilothermia (inability to regulate temperature).
6. Arcuate nucleus: Produce releasing hormones and _____________ factors, which pass through hypophyseal-________ ______ to reach _____________ pituitary gland. _______________ projections from arcuate nuclei inhibit ____________ secretion from anterior pituitary. Damage leads to _____________ (milk discharge) and ________________.
6. Arcuate nucleus: Produce releasing hormones and inhibitory factors, which pass through hypophyseal-portal veins to reach anterior pituitary gland. Dopaminergic projections from arcuate nuclei inhibit prolactin secretion from anterior pituitary. Damage leads to galactorrhea (milk discharge) and amenorrhea.
7. Preoptic nucleus: ______ release which stimulates release of ___ and _____. Damage before puberty leads to arrest of _________ ________________. Damage after puberty leads to _____________ and _____________.
7. Preoptic nucleus: GnRH release which stimulates release of LH and FSH. Damage before puberty leads to arrest of sexual development. Damage after puberty leads to amenorrhea and impotence.
8. Paraventricular and Supraoptic nuclei: Synthesizes neuropeptides ____ and ___________ which are transported via _________________________ tract to Posterior pituitary and stored there. Damage leads to Diabetes ____________ characterized by ______________ and _________.
8. Paraventricular and Supraoptic nuclei: Synthesizes neuropeptides ADH and oxytocin which are transported via supraopticohypophyseal tract to Posterior pituitary and stored there. Damage leads to Diabetes insipidus characterized by polydipsia and polyuria.
9. Suprachiasmatic nucleus: Some of the periodic activities of mammals controlled by the Suprachiasmatic Nucleus are length and time of _______, hormone levels, activity, body _____________, ___________ functions etc. Damage leads to damage to the _______________ of these activities.
9. Suprachiasmatic nucleus: Some of the periodic activities of mammals controlled by the Suprachiasmatic Nucleus are length and time of sleep, hormone levels, activity, body temperature, digestive functions etc. Damage leads to damage to the periodicity of these activities.
ANS The function of the autonomic nervous system is to _________, at a constant level, the internal environment of the body (homeostasis) This system regulates ___________ functions blood pressure heart rate respiration body temperature glandular secretion digestion reproduction Based on the nature of its functions, the autonomic nervous system is also called the _____________ or ____________ nervous system. The system consists of both __________ and ______________ components
ANS The function of the autonomic nervous system is to maintain, at a constant level, the internal environment of the body (homeostasis) This system regulates involuntary functions blood pressure heart rate respiration body temperature glandular secretion digestion reproduction Based on the nature of its functions, the autonomic nervous system is also called the involuntary or vegetative nervous system. The system consists of both afferent and efferent components
Adrenal Medulla The adrenal medulla secretes __________________ into the blood the, and therefore has ___________ ____________. The adrenal medulla acts as a secretory extension of the ______________ nervous system. The adrenal catecholamines have the same effects and mechanism of action as their neuro-counterparts a simple example of the interaction of nervous and endocrine systems. Hypothalamus-pituitary-adrenal axis illustrating factors regulating the secretion of _________________________________ hormone (CRH). ACTH, _______________________ hormone.
Adrenal Medulla The adrenal medulla secretes catecholamines into the blood the, and therefore has autonomic regulation. The adrenal medulla acts as a secretory extension of the sympathetic nervous system. The adrenal catecholamines have the same effects and mechanism of action as their neuro-counterparts a simple example of the interaction of nervous and endocrine systems. Hypothalamus-pituitary-adrenal axis illustrating factors regulating the secretion of corticotropin-releasing hormone (CRH). ACTH, adrenocorticotropic hormone.
Ant. Pit. Cells and Hormones Pars Distalis (PD) 4- Gonadotropes (FSH & LH cells) produce __________ __________ (LH) & follicle-stimulating hormone (FSH) FSH & LH release regulated by ___________________________ hormone (GnRH) 5- _________________ (TSH cells) produce thyroid-stimulating hormone (TSH) TSH release is regulated by ______________________ hormone [TRH(+) and somatostatin (-)] 6- Folliculo-stellate cells ____ ________ produce hormones ? May regulate hormone release from other _____ _______ cells ? Pars Intermedia (PI) Function unclear - may be involved in a- or ______________, _____ Pars Tuberalis (PT) highly ___________ ________, involved in (3)
Ant. Pit. Cells and Hormones Pars Distalis (PD) 4- Gonadotropes (FSH & LH cells) produce luteinizing hormone (LH) & follicle-stimulating hormone (FSH) FSH & LH release regulated by gonadotropin-releasing hormone (GnRH) 5- Thyrotropes (TSH cells) produce thyroid-stimulating hormone (TSH) TSH release is regulated by thyrotropin-releasing hormone [TRH(+) and somatostatin (-)] 6- Folliculo-stellate cells DO NOT produce hormones ? May regulate hormone release from other pars distalis cells ? Pars Intermedia (PI) Function unclear - may be involved in a- or b-endorphin, MSH Pars Tuberalis (PT) highly vascular region, involved in ACTH, FSH, LH
Anterior Pituitary: Cells and Hormones Anterior lobe (Adenohypophysis) - glandular (endocrine) Pars Distalis (PD) 1- Somatotropes (GH cells) Produce growth hormone (GH) GH release regulated by hypothalamic hormones [GHRH (+) & somatostatin (-)] and ghrelin (from stomach) most prevalent cells (50%) 2- Lactotropes (PRL cells, mammotropes) Produce prolactin (PRL) PRL synthesis/secretion regulated by dopamine, TRH, VIP and somatostatin 3- Corticotropes (ACTH cells) Produce proopiomelanocortin (POMC) POMC cleaved in corticotropes into adrenocorticotropic hormone (ACTH), b-endorphin, enkephalin, b-lipotrophic hormone (b-LPH), melanocyte- stimulating hormone (MSH) ACTH release regulated by corticotropin-releasing hormone (CRH)
Anterior Pituitary: Cells and Hormones Anterior lobe (Adenohypophysis) - glandular (endocrine) Pars Distalis (PD) 1- Somatotropes (GH cells) Produce growth hormone (GH) GH release regulated by hypothalamic hormones [GHRH (+) & somatostatin (-)] and ghrelin (from stomach) most prevalent cells (50%) 2- Lactotropes (PRL cells, mammotropes) Produce prolactin (PRL) PRL synthesis/secretion regulated by dopamine, TRH, VIP and somatostatin 3- Corticotropes (ACTH cells) Produce proopiomelanocortin (POMC) POMC cleaved in corticotropes into adrenocorticotropic hormone (ACTH), b-endorphin, enkephalin, b-lipotrophic hormone (b-LPH), melanocyte- stimulating hormone (MSH) ACTH release regulated by corticotropin-releasing hormone (CRH)
Antidiuretic Hormone - Increases H2O absorption in the Kidneys ADH release is triggered by two factors: 1. neuronal impulses from afferent sources of the _____________ nucleus (response to sudden increases in ____________ ________) 2. the sensory properties of the __________ ______ that enable them to sense changes in ________ ___________ The SO and PV nuclei serve as ______________________ E.g. an increase in osmotic pressure from such (________ fluid intake, ___________ amount of salt intake, or fluid ______ due to diarrhea or sweating), SO neurons discharge more ________ and release increased amounts of _____ into the ____________ ____ The primary target of ADH is the _______ ___________ _________ of the kidney causing _____________ of excess water, thus allowing the blood to re-establish __________________
Antidiuretic Hormone - Increases H2O absorption in the Kidneys ADH release is triggered by two factors: 1. neuronal impulses from afferent sources of the supraoptic nucleus (response to sudden increases in emotional states) 2. the sensory properties of the supraoptic nuclei that enable them to sense changes in blood osmolarity The SO and PV nuclei serve as osmoreceptors E.g. an increase in osmotic pressure from such (reduced fluid intake, increased amount of salt intake, or fluid loss due to diarrhea or sweating), SO neurons discharge more rapidly and release increased amounts of ADH into the vascular system The primary target of ADH is the distal convoluted tubules of the kidney causing reabsorption of excess water, thus allowing the blood to re-establish osmolality
Autonomic Reflexes Many visceral functions of the body are regulated by ___________ __________. Cardiovascular Autonomic Reflexes - Several reflexes in the cardiovascular system help to control especially the __________ _________ _________ and the heart rate e.g. ______________ reflex Gastrointestinal Autonomic Reflexes. The uppermost part of the gastrointestinal tract and the rectum are controlled principally by _______________ reflexes. Other Autonomic Reflexes. Emptying of the urinary bladder - ___________ reflexes. Sexual reflexes
Autonomic Reflexes Many visceral functions of the body are regulated by autonomic reflexes. Cardiovascular Autonomic Reflexes - Several reflexes in the cardiovascular system help to control especially the arterial blood pressure and the heart rate e.g. baroreceptor reflex Gastrointestinal Autonomic Reflexes. The uppermost part of the gastrointestinal tract and the rectum are controlled principally by autonomic reflexes. Other Autonomic Reflexes. Emptying of the urinary bladder - micturition reflexes. Sexual reflexes
________ __________________ that can lead to death occurs in approximately 30% of those infected. Antibodies against the parasitic antigens have been found to bind to the ____________ ________________________ and ___ ___________________ receptors These antibodies not only trigger __________________ responses that destroy heart muscle but also act as ___________ at these receptors and cause inappropriate responses of the cardiovascular system to changing external demands.
Chronic cardiomyopathy that can lead to death occurs in approximately 30% of those infected. Antibodies against the parasitic antigens have been found to bind to the cardiac β-adrenergic and M2 acetylcholine receptors These antibodies not only trigger autoimmune responses that destroy heart muscle but also act as agonists at these receptors and cause inappropriate responses of the cardiovascular system to changing external demands.
Clinical Correlation Chagas' disease is the result of infection by the parasite ___________________ _________. About 18 million people are infected worldwide, and approximately 50,000 die each year as a result of complications from the disease. The most serious forms involve enlargement of the ______________,___________, and _________. Loss of __________________ control is a significant component of the initial stages of the disease; shortly after the initial infection, the parasympathetic neurons innervating the heart, esophagus, and colon are destroyed, which leads to ___________ (and potentially sudden death) and ________________.
Clinical Correlation Chagas' disease is the result of infection by the parasite Trypanosoma cruzi. About 18 million people are infected worldwide, and approximately 50,000 die each year as a result of complications from the disease. The most serious forms involve enlargement of the esophagus, colon, and heart. Loss of parasympathetic control is a significant component of the initial stages of the disease; shortly after the initial infection, the parasympathetic neurons innervating the heart, esophagus, and colon are destroyed, which leads to arrhythmias (and potentially sudden death) and aperistalsis.
Connections of Hypothalamus (Afferents) Significant modulation of ___________________ processes is mediated by different groups of ___________ fibers that originate primarily in the ________ system & __________ formation FORNIX: ______________ fornix projects to __ and __________ nucleus of thalamus Branch of fornix arises from the subicular cortex of the _____________ formation, and H component terminates largely in the __________ H and __________ bodies
Connections of Hypothalamus (Afferents) Significant modulation of hypothalamic processes is mediated by different groups of afferent fibers that originate primarily in the limbic system & reticular formation FORNIX: postcommissural fornix projects to H and anterior nucleus of thalamus Branch of fornix arises from the subicular cortex of the hippocampal formation, and H component terminates largely in the medial H and mammillary bodies
Middle Tuberal Region DMN - In animals, _______ behavior results when this nucleus is stimulated Arcuate - _______ receptor (? feeding behavior), ___________ releasing hormone (DA) VMN - When stimulated, it ___________ the urge to eat. Bilateral destruction results in _____________, __________. ______ behavior, _____ behavior (lordosis), _____________ control (ER, PR expressed)
DMN - In animals, rage behavior results when this nucleus is stimulated Arcuate - leptin receptor (? feeding behavior), prolactin releasing hormone (DA) VMN - When stimulated, it inhibits the urge to eat. Bilateral destruction results in hyperphagia, obesity. Rage behavior, sex behavior (lordosis), endocrine control (ER, PR expressed)
Efferent Pathways: Mammilary Bodies Mammillothalamic tract (to __________ ___________ nucleus) which forms part of _______ circuit = _________________ memory Mammillotegmental tract (to ________ tegmentum) and autonomic nuclei in lower brainstem and spinal cord = ? Autonomic functions Mammillary peduncle (to ___________ _____________) = ? Autonomic functions
Efferent Pathways: Mammilary Bodies Mammillothalamic tract (to anterior thalamic nucleus) which forms part of Papez circuit = short-term memory Mammillotegmental tract (to midbrain tegmentum) and autonomic nuclei in lower brainstem and spinal cord = ? Autonomic functions Mammillary peduncle (to reticular formation) = ? Autonomic functions
Efferent pathways: __________ region (arcuate nucleus) ________ hypothalamus To adenohypophysis (ant. pituitary) via __________________________ tract (axons) to ___________________________ portal system (capillaries) = releasing hormones (stimulatory) GHRH (_________) → _______________ TRH (________________ region) → ________________ CRH (3) → ____________ GnRH (wide distribution, _________, ____________) → Gonadotropes Prolactin releasing factor (?) → Lactotropes = ________________ hormones somatostatin (__________ region, ______ hypo) → (3)
Efferent pathways: Tuberal region (arcuate nucleus) Medial hypothalamus To adenohypophysis (ant. pituitary) via tuberoinfundibular tract (axons) to hypothalamohypophyseal portal system (capillaries) = releasing hormones (stimulatory) GHRH (arcuate) → Somatotropes TRH (periventricular region) → Thyrotropes CRH (paraventricular, supraoptic, arcuate) → Corticotropes GnRH (wide distribution, post. hypo, arcuate) → Gonadotropes Prolactin releasing factor (?) → Lactotropes = inhibitory hormones somatostatin (preoptic region, ant. hypo) → Somatotropes, Thyrotropes, Lactotropes
Function of the Adrenal Medulla Sympathetic innervation of the _________ ___________. Preganglionic sympathetic axons terminate on the ________________ cells. When stimulated, cells release ____________ (80%) and, _______________ (20%). Stimulates of cardiovascular function and modulate _____________ _______ Helps the body deal with ______ Epinephrine and norepinephrine are both potent agonists for _________________ and for ___ and ___ receptors Epinephrine is more potent ___ receptors agonist than ___________________.
Function of the Adrenal Medulla Sympathetic innervation of the adrenal medulla. Preganglionic sympathetic axons terminate on the chromaffin cells. When stimulated, cells release epinephrine (80%) and, norepinephrine (20%). Stimulates of cardiovascular function and modulate metabolic rate Helps the body deal with stress Epinephrine and norepinephrine are both potent agonists for α-receptors and for β1 and β2 receptors Epinephrine is more potent β2 receptors agonist than norepinephrine.
Pituitary Hormone GOAT FLAP (8)
GOAT FLAP Growth Hormone Oxytocin Adrenocorticotropic Hormone Thyroid Stimulating Hormone Follicle Stimulating Hormone Luteinizing Hormone Antidiuretic Hormone (ADH) Prolactin
Hypophysectomy (pituitary removal) Because posterior pituitary hormones are synthesized in the _________________ rather than the pituitary, hypophysectomy (pituitary removal) does not necessarily permanently disrupt synthesis and secretion of these hormones. Immediately after hypophysectomy, secretion of the hormones _______________ However, over a period of weeks, the severed proximal end of the tract __________ will form around the __________ ____________. Secretion of hormone resumes from the __________ ________. In contrast, a lesion higher up on the pituitary stalk can lead to loss of __________ _______ _____ in the _____ and _____.
Hypophysectomy (pituitary removal) Because posterior pituitary hormones are synthesized in the hypothalamus rather than the pituitary, hypophysectomy (pituitary removal) does not necessarily permanently disrupt synthesis and secretion of these hormones. Immediately after hypophysectomy, secretion of the hormones decreases. However, over a period of weeks, the severed proximal end of the tract pituicytes will form around the neuron terminals. Secretion of hormone resumes from the proximal end. In contrast, a lesion higher up on the pituitary stalk can lead to loss of neuronal cell bodies in the PVN and SON.
Hypothalamic Efferents to Pituitary Effects on neuroendocrine functions to the posterior Pit. is from the _______________ and ____________ nuclei (have similarities) Both have _______ cells, both have ________ projections that reach rich ___________ _______ in the posterior Pit. _______ (antidiuretic hormone, vasopressin) - water homeostasis and _____________ of body fluids ____________ - promote contraction of uterine smooth muscle & breast myoepithelial cells (lactation), _______ balance Hypothalamoneurohypophyseal tracts are used by the _________________ and _______________ nuclei as projection pathways to the ______________ pituitary.
Hypothalamic Efferents to Pituitary Effects on neuroendocrine functions to the posterior Pit. is from the Paraventricular and Supraoptic nuclei (have similarities) Both have large cells, both have axonal projections that reach rich vascular beds in the posterior Pit. ADH (antidiuretic hormone, vasopressin) - water homeostasis and osmolarity of body fluids Oxytocin - promote contraction of uterine smooth muscle & breast myoepithelial cells (lactation), fluid balance Hypothalamoneurohypophyseal tracts are used by the paraventricular and supraoptic nuclei as projection pathways to the posterior pituitary.
Hypothalamus is divided into medial and lateral by the ________ Lateral hypothalamus - induce _________, ____________ & ______ (predatory/attack) Medial hypothalamus - suppress _________, ____________ & ______ (defensive)
Hypothalamus is divided into medial and lateral by the fornix Lateral hypothalamus - induce feeding, aggression & rage (predatory/attack) Medial hypothalamus - suppress feeding, aggression & rage (defensive)
Hypothalamus: Drinking behavior Detects ↑ blood ____________ - ________ - _________ Lateral hypothalamus (thirst center) → activate desire to drink _________________ and ____________ nuclei → ADH release Diabetes insipidus results with lesion of __________ and/or ____________ nuclei. __ ADH release = __ H2O intake, __ urine volume
Hypothalamus: Drinking behavior Detects ↑ blood osmolarity - intake - excretion Lateral hypothalamus (thirst center) → activate desire to drink Paraventricular and supraoptic nuclei → ADH release Diabetes insipidus results with lesion of supraoptic and/or paraventricular nuclei. ↓ ADH release = ↑ H2O intake, ↑ urine volume
Hypothalamus: Aggression and Rage Medial hypothalamus stimulation - defensive rage behavior in cat = _______________, _______________ (hiss, growl), pupil ____________, sympathetic response projection to ________ ________ _____, ______________, _________ system Lateral hypothalamus - ____________ behavior (quiet biting, attack) in cat few signs projection to ____________ PAG, brainstem, limbic system
Hypothalamus: Aggression and Rage Medial hypothalamus stimulation - defensive rage behavior in cat = piloerection, vocalization (hiss, growl), pupil dilation, sympathetic response projection to dorsal midbrain PAG, brainstem, limbic system Lateral hypothalamus - predatory behavior (quiet biting, attack) in cat few signs projection to midbrain PAG, brainstem, limbic system
Hypothalamus: Biological Rhythms Suprachiasmatic nucleus (SCN) receives input from _______ ___________ neurons orchestrates rhythms throughout body _______ genes have been ID in the SCN and believed to form the basis of __________ in the ___________
Hypothalamus: Biological Rhythms Suprachiasmatic nucleus (SCN) receives input from retina ganglia neurons orchestrates rhythms throughout body Clock genes have been ID in the SCN and believed to form the basis of rhythms in the neurons
Hypothalamus: Cardiovascular _____________ hypothalamus & ___________ region (parasymp) - ______________ BP & heart rate _________ ___________ hypothalamus & ____________ hypothalamus (sympathetic) - increase BP & heart rate Act via: (2) (parasym) (2) (symp) of Spinal Cord
Hypothalamus: Cardiovascular Anterior hypothalamus & Preoptic region (parasymp) - decrease BP & heart rate Posterior medial hypothalamus & lateral hypothalamus (sympathetic) - increase BP & heart rate Act via: Nuc ambiguus, Dorsal motor of X (parasym) Ventrolateral medulla & Solitary nucleus to regulate IML (symp) of Spinal Cord
Hypothalamus: Feeding behavior Medial hypothalamus _____________ feeding - 'satiety center' a 'set-point' that regulates hypothalamic control of food intake lesions = __ intake, __ weight gain, hyperphagia involvement of CCK (__________________), _____________, ___________________ Lateral hypothalamus induces feeding - '__________ ____________' lesions = lost motivation for food, ↓ _________ ____________ involvement of sensory signals (___________ & _______), ________________ _________________ and ____________ nuclei are also involved
Hypothalamus: Feeding behavior Medial hypothalamus suppresses feeding - 'satiety center' a 'set-point' that regulates hypothalamic control of food intake lesions = ↑ intake, ↑ weight gain, hyperphagia involvement of CCK (cholecystokinin), glucagon, neurotensin Lateral hypothalamus induces feeding - 'feeding center' lesions = lost motivation for food, ↓ appetite, aphagia involvement of sensory signals (olfaction & taste), amygdala Paraventricular and arcuate nuclei are also involved
Hypothalamus: Sexual Behavior _______________ hypothalamus Estrogen and progesterone receptors expressed ___________ stimulated (sexual response in female rats to allow intromission by a male) Anterior (preoptic) hypothalamus GnRH released (Ant. Pit.) - increase ____________ levels Testosterone acts on __________ nuclei - sexual behavior characteristics Preoptic region is sexually ___________ in rats (larger in males)
Hypothalamus: Sexual Behavior Ventromedial hypothalamus Estrogen and progesterone receptors expressed Lordosis stimulated (sexual response in female rats to allow intromission by a male) Anterior (preoptic) hypothalamus GnRH released (Ant. Pit.) - increase estrogen levels Testosterone acts on preoptic nuclei - sexual behavior characteristics Preoptic region is sexually dimorphic in rats (larger in males)
Hypothalamus: ________________ regulation Change in blood temperature detected by temperature sensitive neurons Anterior (& _________ region) hypothalamus (__temp __neuron activity) - causes ___________ & SpCd to activate ______________ & _____________ - responsive to ____________ (anti-pyrogenic region) - '_____ _____ ________' Posterior-lateral hypothalamus (__temp __neuron activity) - brainstem & SpCd to vasoconstrict, __ heart rate, __ basal metabolic rate, shivering, piloerection - '____ ___________ _________'
Hypothalamus: Temperature regulation Change in blood temperature detected by temperature sensitive neurons Anterior (& preoptic region) hypothalamus (↑temp ↑neuron activity) - causes brainstem & SpCd to activate vasodilation & sweating - responsive to pyrogens (anti-pyrogenic region) - 'heat loss center' Posterior-lateral hypothalamus (↓temp ↑neuron activity) - brainstem & SpCd to vasoconstrict, ↑ heart rate, ↑ basal metabolic rate, shivering, piloerection - 'heat conservation center'
Mammillary Peduncle Arises mainly from the __________ and __________ ____________ nuclei of the midbrain and may serves as a relay for ascending impulses to the H from lower regions of the ____________ ___________ Ascending fibers from the dorsal tegmental nuclei terminate principally in the mammillary bodies, while those in the _________ tegmental pass through the ________ ________ ________ to the more ________ levels of H and _________ structure
Mammillary Peduncle Arises mainly from the ventral and dorsal tegmental nuclei of the midbrain and may serves as a relay for ascending impulses to the H from lower regions of the brainstem tegmentum Ascending fibers from the dorsal tegmental nuclei terminate principally in the mammillary bodies, while those in the ventral tegmental pass through the medial forebrain bundle to the more rostral levels of H and limbic structure
Mammillary bodies: Part of _______ circuit involved in __________. Damaged in _____________ syndrome (___________ deficiency in chronic alcoholism) leading to both ____________ and _____________ amnesia with confabulations.
Mammillary bodies: Part of papez circuit involved in memory. Damaged in Korsakoff syndrome (thiamine deficiency in chronic alcoholism) leading to both anterograde and retrograde amnesia with confabulations.
Medial Forebrain Bundle Traverses the ________________ extent of the __________ H Efferents are from ___________ to _______________ (PAG & nuclei) Afferents are from _____________ (monoamine) to ______________ & _____________ (including cortex); septal area & diagonal band of ____________ to Lat. & Med. _______ & ______________ bodies.
Medial Forebrain Bundle Traverses the rostro-caudal extent of the lateral H Efferents are from hypothalamus to brainstem (PAG & nuclei) Afferents are from brainstem (monoamine) to hypothalamus & forebrain (including cortex); septal area & diagonal band of Broca to Lat. & Med. Hypo & Mammillary bodies.
Medial Preoptic - contains the _____________ ______________ nucleus contains about 2x as many cells in adult men as adult women
Medial Preoptic - contains the sexually dimorphic nucleus contains about 2x as many cells in adult men as adult women
Midbrain Periaqueductal Gray Midbrain PAG matter is functionally related to the ________ ___ and reciprocal connections with parts of the _________ __ Dorsal part of the midbrain PAG contains both ___________ and ________________ projections Ascending projections reach the _______________ half of the medial hypothalamus and thus serve as a __________ mechanism with respect to several of the functions of the medial H, which are mediated via their _____________ projections to the ___________ _____
Midbrain Periaqueductal Gray Midbrain PAG matter is functionally related to the medial H and reciprocal connections with parts of the medial H Dorsal part of the midbrain PAG contains both ascending and descending projections Ascending projections reach the posterior half of the medial hypothalamus and thus serve as a feedback mechanism with respect to several of the functions of the medial H, which are mediated via their descending projections to the midbrain PAG
Monoaminergic Pathways H and other forebrain regions receive monoaminergic projections from the _______ ___________ (containing serotonin) _______ ___________ (containing norepinephrine) ________ __________ _____ (containing dopamine) These inputs from the _____________ ______________ together with the inputs from _________ structures, provide significant modulation of hypothalamic processes
Monoaminergic Pathways H and other forebrain regions receive monoaminergic projections from the raphe complex (containing serotonin) Locus ceruleus (containing norepinephrine) Ventral tegmental area (containing dopamine) These inputs from the brainstem tegmentum together with the inputs from limbic structures, provide significant modulation of hypothalamic processes
Oxytocin The main actions of oxytocin are: Contractions of the ________________ cells around the nipple of the ________________ gland for the ejection of milk (ejection reflex) Contractions of the _________ __________ of the uterus during birth trigger involves a: Sensory stimuli associated with suckling produce sensory impulses that ascend to the ___________ thru ________________ pathways Increased neuronal discharges of the ____________________ nucleus and increased secretion of __________ into the circulatory system where it acts on the _______________ _______.
Oxytocin The main actions of oxytocin are: Contractions of the myoepithelial cells around the nipple of the mammary gland for the ejection of milk (ejection reflex) Contractions of the smooth muscles of the uterus during birth trigger involves a: Sensory stimuli associated with suckling produce sensory impulses that ascend to the forebrain thru multi-synaptic pathways Increased neuronal discharges of the paraventricular nucleus and increased secretion of oxytocin into the circulatory system where it acts on the mammary gland.
Pheochromocytoma is a tumor of ___________ tissue that produces excessive quantities of __________________. Commonly ________ ____________ tumors, but can occur in other _____________ cells of the ________________ __________ ___________. They are the most common cause of hyperfunctioning ___________ ___________. The catecholamine most frequently elevated is _________________. Symptoms include(5)
Pheochromocytoma is a tumor of chromaffin tissue that produces excessive quantities of catecholamines. Commonly adrenal medullary tumors, but can occur in other chromaffin cells of the autonomic nervous system. They are the most common cause of hyperfunctioning adrenal medullary. The catecholamine most frequently elevated is norepinephrine. Symptoms include hypertension, headaches (from hypertension), sweating, anxiety, palpitations, and chest pain.
Pituitary adenomas :(2)
Pituitary adenomas : Gigantism, Acromegaly
Pituitary adenomas : Prolactinoma Of the primary brain tumors ________ are pituitary _____________ Pituitary tumors are relatively common, accounting for about 15% of all _________ ________ tumors. Most originate in the __________________ and are typically nonsecretory benign ______________. Tumors of the neurohypophysis are rare and include _____________, ___________ _______ tumors, and potentially any primary tumor of the __________.
Pituitary adenomas : Prolactinoma Of the primary brain tumors 12-15% are pituitary adenomas Pituitary tumors are relatively common, accounting for about 15% of all primary brain tumors. Most originate in the adenohypophysis and are typically nonsecretory benign adenomas. Tumors of the neurohypophysis are rare and include metastasis, granular cell tumors, and potentially any primary tumor of the neuraxis.
Pituitary: Embryonic development of the two lobes originate from different sources Rathke's pouch → __________ lobe - ____________ epithelial tissue originate from different sources (_________________) Neuroectoderm → ____________ lobe - ________ secretory tissue outgrowth from the hypothalamus (____________________)
Pituitary: Embryonic development of the two lobes originate from different sources Rathke's pouch → Anterior lobe - glandular epithelial tissue originate from different sources (Adenohypophysis) Neuroectoderm → Posterior lobe - neural secretory tissue outgrowth from the hypothalamus (Neurohypophysis)
Posterior - Mammilary Region LN - Lesions cause ___________ and _____________
Posterior - Mammilary Region LN - Lesions cause anorexia and starvation
Serotonergic neurons and nuclei in the brainstem and their projections Dorsal raphe nucleus and raphe nuclei in ______ - axons project to ___________, _________ system and most areas of __________ ____________ Raphe nuclei in medulla - axons project to ______ ________ and _______ _________; attenuate pain sensation via regulation of _____________ release
Serotonergic neurons and nuclei in the brainstem and their projections Dorsal raphe nucleus and raphe nuclei in pons - axons project to thalamus, limbic system and most areas of cerebral cortex Raphe nuclei in medulla - axons project to brain stem and spinal cord; attenuate pain sensation via regulation of enkephalin release
Projections from the Medial Forebrain Bundle (Lateral H) Ascending fibers with MFB supply the _________ ________, ____________ region, and nuclei of the diagonal band of _________ Some fibers of the far rostral lateral H have _______ _______ that project as far as the ________________ formation, __________ cortex and other parts of the ________ _______ lobes This path could provide CC with direct information concerning the ___________ ________ as well as synchronize cortical activity with H functions Other fibers ascending in the MFB enter the _____ _________ and terminate in the lateral habenular nucleus Descending fibers of the lateral H pass thru _____ to ________ regions of _________ ______ and other regions of eh midbrain and ____________ ______________
Projections from the Medial Forebrain Bundle (Lateral H) Ascending fibers with MFB supply the septal area, preoptic region, and nuclei of the diagonal band of Broca Some fibers of the far rostral lateral H have long axons that project as far as the hippocampal formation, prefrontal cortex and other parts of the frontal parietal lobes This path could provide CC with direct information concerning the internal milieu as well as synchronize cortical activity with H functions Other fibers ascending in the MFB enter the stria medullaris and terminate in the lateral habenular nucleus Descending fibers of the lateral H pass thru MFB to ventral regions of midbrain PAG and other regions of eh midbrain and pontine tegmentum
Projections from the Medial Hypothalamus Fibers originating from the medial H have both _____________ and ___________ projections Ascending projections reach the medial nucleus of ______________ A feedback pathway that regulates _____________ __________ and related hypothalamic processes Descending fibers project principally to the _________ half of the __________ _________ Enables emotional (3) and autonomic (2) PAG then project to the lower _______________, ___________________ (pontine tegmentum, solitary nucleus, ventrolateral medulla, dorsal motor nucleus of CN X, and intermediolateral cell column of the spinal cord) and somatic __________ __________ of the lower ______________ and ________ _____
Projections from the Medial Hypothalamus Fibers originating from the medial H have both ascending and descending projections Ascending projections reach the medial nucleus of Amygdala A feedback pathway that regulates emotional behavior and related hypothalamic processes Descending fibers project principally to the dorsal half of the midbrain PAG Enables emotional (aggression, rage, flight) and autonomic (marked changes in heart rate and BP) PAG then project to the lower sympathetic, parasympathetic (pontine tegmentum, solitary nucleus, ventrolateral medulla, dorsal motor nucleus of CN X, and intermediolateral cell column of the spinal cord) and somatic motor regions of the lower brainstem and spinal cord
Supraoptic SC Receives direct input from the _______ Sends outputs to the _____________, ________ gland, and other ______ regions. Control the production of various hormones, which regulate behaviors like __________ and ____________.
Supraoptic SC Receives direct input from the retina Sends outputs to the hypothalamus, pineal gland, and other brain regions. Control the production of various hormones, which regulate behaviors like feeding and sleeping.
Thalamohypothalamic Fibers Mediodorsal thalamic nucleus receives major inputs from the ___________ _______ and portions of the __________ _______ _______ Fibers then project to _________ ________ thalamic nuclei Then a chain of neurons then pass rostrally through ________ nuclei Neurons that arise from the _________ ________ of the midline thalamus (nucleus _________) project to the anterior __________ ____ This is how the ___________ ___________ and __________ __________ _________ can regulate functions associated with the lateral H
Thalamohypothalamic Fibers Mediodorsal thalamic nucleus receives major inputs from the prefrontal cortex and portions of the anterior cingulate gyrus Fibers then project to posterior midline thalamic nuclei Then a chain of neurons then pass rostrally through midline nuclei Neurons that arise from the rostral aspect of the midline thalamus (nucleus reuniens) project to the anterior lateral H This is how the prefrontal cortex and anterior cingulate gyrus can regulate functions associated with the lateral H
The Pituitary Hormones
The Pituitary Hormones
The hypothalamoneurohypophyseal portal vasculature system. The peptides which are synthesized in the ____ _______, are transported down the hypothalmohypophyseal tract and are released into the ________ _____________ These neurons referred to as ___________________ Fibers from these hypothalamic nuclei also reach the __________ __________, where the hormones are released into the ___________ ________ From the vascular beds, the hormones can be transported elsewhere, including the ____ _____ The AP in response to different types of stimuli triggers that release the hormones from the nerve endings in the _____ ____ ?? Nuclei
The hypothalamoneurohypophyseal portal vasculature system. The peptides which are synthesized in the cell bodies, are transported down the hypothalmohypophyseal tract and are released into the portal circulation These neurons referred to as neurosecretory Fibers from these hypothalamic nuclei also reach the median eminence, where the hormones are released into the vascular beds From the vascular beds, the hormones can be transported elsewhere, including the ant. Pit. The AP in response to different types of stimuli triggers that release the hormones from the nerve endings in the post. Pit. Paraventricular/Supraoptic Nuclei
The hypothalamus is the central regulator of ______________ Controlling _________, ________, ________ _________, ______________ cycle Endocrine control via the ___________ Autonomic control Limbic mechanisms (Mnemmonic: HEAL) Regulation of homeostasis is controlled via: Hormonal (Endocrine) system (Pituitary and Adrenal Glands) Autonomic nervous system Sympathetic nervous system Parasympathetic nervous system Enteric nervous system
The hypothalamus is the central regulator of homeostasis Controlling hunger, thirst, sexual desire, sleep-wake cycle Endocrine control via the pituitary Autonomic control Limbic mechanisms (Mnemmonic: HEAL) Regulation of homeostasis is controlled via: Hormonal (Endocrine) system (Pituitary and Adrenal Glands) Autonomic nervous system Sympathetic nervous system Parasympathetic nervous system Enteric nervous system
Ventral Amygdalofugal Pathway Arises chiefly from the ______________ amygdala and parts of the adjoining ___________ cortex Course medially from the amygdala into the ___________ ___________ where many terminate Other axons continue to pass in a caudal direction, where most synapse in the midbrain ________________________________ Involved in ______________ (aggression, rage, flight), ? ____________
Ventral Amygdalofugal Pathway Arises chiefly from the basolateral amygdala and parts of the adjoining pyriform cortex Course medially from the amygdala into the lateral H where many terminate Other axons continue to pass in a caudal direction, where most synapse in the midbrain periaqueductal gray (PAG) Involved in emotional (aggression, rage, flight), ? autonomic
Zona glomerulosa Cells secret ______________ Extracellular concentrations of _____________ ____ and __________, modulate _________________ secretion. Zona fasciculata Secretes the ___________________, _________ and ______________, and small amounts of adrenal _______________ and _____________. controlled in by the hypothalamic-pituitary axis via _______________________ __________ (ACTH). Zona reticularis, the ______ layer of the cortex Secretes the ________ _________ __________________________ (DHEA), ____________________, ___________ and some ____________________. ACTH regulates secretion of these cells, cortical androgen-stimulating hormone may also be involved
Zona glomerulosa Cells secret aldosterone Extracellular concentrations of angiotensin II and potassium, modulate aldosterone secretion. Zona fasciculata Secretes the glucocorticoids, cortisol and corticosterone, and small amounts of adrenal androgens and estrogens. controlled in by the hypothalamic-pituitary axis via adrenocorticotropic hormone (ACTH). Zona reticularis, the deep layer of the cortex Secretes the adrenal androgens dehydroepiandrosterone (DHEA), androstenedione, estrogens and some glucocorticoids. ACTH regulates secretion of these cells, cortical androgen-stimulating hormone may also be involved
