FINAL EXAM Lecture 16 & 17 Diencephalon & Hypothalamus Flashcards
The most dorsal part of the diencephalon
It forms a caplike covering over the thalamus
Epithalamus
The Epithalamus is the _______ and _________ part of the ___________.
Smallest
Oldest
Diencephalon
The Epithalamus is composed of: (3)
- Pineal Body
- Habenular Nuclei
- Caudal Commissure
Function of the Epithalamus:
It is functionally and anatomically linked to the limbic system. It is involved in regulating reproductive functions (mating behavior; responsible for postpartum maternal behavior.) Melatonin, secreted by the pineal gland at night, is concerned with biological timing including sleep induction.
Melatonin is secreted by the _______ at _______.
It is concerned with biological timing including __________ ________.
Pineal gland
Night
Sleep Induction
This is located ventral to the thalamus and _______ to the hypothalamus & is only present in ________
Subthalamus
Lateral
Mammals
The Subthalamus is involved in the ________ ___ _________ ____________, which selects ______ and suppreses _______ movements.
Generation of Rhythmic Movements
Wanted
Unwanted
Stimulation of the ________ provides the most effective treatment for late-stage Parkinson’s disease in humans.
Subthalamus
The largest component of the diencephalon
Thalamus
4 Subdivisions of the Diencephalon
- Epithalamus
- Subthalamus
- Thalamus
- Hypothalamus
The thalamus is:
Composed of a large number of ______. The two you should know are: ______ & _________ (and their main functions).
Nuclei
- Lateral Geniculate - Vision
- Medial Geniculate - Hearing
The _______ serves as the great sensory receiving area (receives sensory input from all sensory pathways EXCEPT _________) and relays sensory information to the _______ ________.
Thalamus
Olfaction
Cerebral Cortex
What nucleus controls circadian rhythms?
Suprachiasmatic Nucleus
The most ventral part of the diencephalon
Hypothalamus
While there are 4 parts to the diencephalon, from a clinical perspective, the most significant component is the ____________, since leasions of this area can cause abnormalities in _________, __________ or _________ __________.
Hypothalamus
Endocrine
Limbic
Autonomic Function
Hypothalamus Function
Most important job is to maintain _________
It does this by: (3)
Homeostasis (the body’s status quo)
Endocrine Secretion
Autonomic Function
Emotions and Drives
Hypothalamus
Endocrine Section - Controls _______ release by the ______ ________.
Hormone
Pituitary Gland
_Hypothalamus _
Autonomic Function -
Integrates autonomic functions via ____ _____ to ______ ______ neurons located in the _____-______ and _______ ________.
Direction Projections
Preganglionic autonomic neurons
Brain-Stem
Spinal Cord
_Hypothalamus _
Emotions & Drives -
It has numberous interconnections with the ______ _____ by which it generates behaviors involved in ____, ______, _____, etc.
Limbic system
Rage
Aggression
Escape
3 Subdivisions of the Hypothalamus
Supraoptic
Tuberal
Mamillary
The most important division in veterinary medicine, it lies above the optic chiams and contains 3 important nuclei.
_Name the division and all 3 nuclei _
Supraoptic Region (of the hypothalamus)
- Supraoptic Nucleus
- Paraventricular Nucleus
- Suprachiasmatic Nucleus
Supraoptic Nucleus
Contains neurons that produce antidiuretic hormone (______ or ________)
Their axons project to the ______ ________ _____ (neurohypophysis) where ____ is released and entes the blood.
ADH
Vasopressin
Posterior Pituitary Gland
ADH
Paraventricular Nucleus
Contains neurons that produce premoninately _______
Oxytocin
Suprachiasmatic Nucleus
Plays a role in ________ _________.
Circadian Rhythms
Tuberal Region
Lies directly anove the ____ _____ and contains cells that produce ________ (_______), which control various aspects of sleep.
Dogs with _______ have a mutation in the _____ receptor gene.
Pituitary gland
Orexins
(Hypocretins)
Narcolepsy
Orexin
Most caudal portion of the hypothalamus comprised primarily of the mamillary bodies - plays a role in _______.
Mamillary Region
Memory
Key Concept
While there are a number of regions that comprise the hypothalamus the ________ region is by far the most important and damage to this area can result in problems with _____ (damage to _____ cells or _____), with ____ ____ (____ _____ ______) and _______ regulation.
Supraoptic Region
Urination - ADH cells or fibers
Circadian Rhythms (Sleep wake cycle)
Temperature Regulation
_Afferent Inputs to the Hypothalamus _
(Fibers coming from other brain regions)
In order to maintain ______ the hypothalamus must receive inputs about the state of the body. The major inputs that convey this information include:
1.
2.
3.
4.
Homeostasis
- Nucleus of Solitary Tract
- Limbic System
- Retina
- Blood
Afferent Inputs to the Hypothalamus
This nucleus collects all of the visceral sensory information from the vagus nerve and sends it to the hypothalamus.
Nucleus of the Solitary Tract
Afferent Inputs to the Hypothalamus
Structures such as the amygdala and olfactory cortex
( Piriform lobe) project to the hypothalamus and help regulate behaviors such as eating and reproduction.
Limbic System via the fornix
_Afferent Inputs to the Hypothalamus _
_______ via direct branches of the optic nerve that go to the suprachiasmatic nucleus
Retina
Afferent Inputs to the Hypothalamus
Hypothalamus has intrinsic receptors including _______ and _____ that monitor _____ and ______ balance;
In addition hypothalamic cells are sensitive to hormone concentrations and glucose levels, etc.
BLOOD
Thermoreceptors
Osmoreceptors
Temperature
Ionic
Major Efferent Projections from the Hypothalamus
Once the hypothalamus is aware of a problem, it fixes the problem via the following routes of communcation:
1.
2.
3.
Ultimatley, through these connections the hypothalamus can control every ____ ____ and can alter _____ _____, ______ _____, and ______ to maintain body homeostasis.
- Neural signals to the autonomic nervous system via projections to the brain stem vagal nuclei and to pregnanglionic nuclei in the spinal cord
- Neural signals to the limbic system
- Endocrine signals to/through the pituitary gland
Endocrine Gland
Blood Pressure
Body Temperature
**Metabolism **
_Pituitary Gland _
Lies beneath the _____ and is formed by ___ distinct parts:
a _____ part, the _____
and
a ______ component derived from _____ _____, called the _________.
Brain
2
Neural part, the Neurohypophysis
Glandular
Oral epithelium
Adneohypophysis
The hypothalamus controls the endocrine system via ____ different routes:
- _______ by secretion of _____ products into the general circulation via the _____ of the ____ ____ ____ (____ and _____).
- _______ by secretion of ______ factors into the local _____ _____ ______ ________ (A vascular plexus that carries these factors from the base of the hypothalamus [an area known as the eminence] to the anterior pituitary). The hypothalamus thus controls _______ _______ hormone synthesis and release via the transport of these factors to the __________.
Endocrine
2
Directly, Neuroendocrine, vasculature, Posterior Pituitary Gland, AHD, Oxytocin
Indirectly, Releasing, Hypophyseal Portal Venous Plexus
Anterior pituitary, adenohypophysis
The hypothalamus is connected directly to the Pituitary gland via the axons of the ______ and ______ nuclei and indirectly via the ____ _____ ______.
Supraoptic
Paraventricular
Hypophyseal Portal System
Hypothalamic Functions
The hyopthalamus:
(1) Controls the release of at least ____ major hormones by the _____, and is involved in (2) _______ regulation, (3) control of _____ and ____ intake, (4) _______ behavior and _________, (5) control of daily cycles in _________ state and behavior, and (6) mediation of _________ response.
8
Hypophysis
Temperature
Food & Water
Sexual & Reproduction
Physiological
Emotional
Hypothalamus secretes ____ and ____ into the circulation which has a direct effect on the ________ ________.
Oxytocin
Vasopressin (ADH)
Endocrine System
Oxytocin is Greek for
Rapid Birth
Oxytocin
Is produced by: ________ in the ________ ______ of the hypothalamus
**Functions: acts on ____ _____ muscle to stimulate myometrial contractions and accelerates _____ (thus oxytocin or synth. derivates of oxytocin can be given to induce ____, eg in the mare). **
Activates ____ _____ _____ in response to suckling (induces contraction of myoepithelial cells in mammary gland). It also acts on the _________ (& nucleus accumbens) to enhance _____ between a male and female once they have mated and between a mother and her newborn.
Neurons, Paraventricular Nuclei
Uterine Smooth Muscle
Parturition
Parturition
Milk Letdown Reflex
Amygdala
Bonding
Vasopressin ( ____ )
Produced by: ______ in the _____ ____
Function: to _______ ______ of ____ in the _____ (via collecting ducts and convoluted tubulues). Thus it decreases _____ production and ______ body water. Capillary density of the ____ _____ is ____ than any other part of the brain and ____ in blood osmolarity _____ release of ADH.
ADH
Neurons, Supraoptic nucleus
Increase, Reabsorption, Water, Kidneys
Urine, Conserves
Supraoptic nucleus, higher, Increases, Stimulate
Diabetes Insipidus
A disorder of _____ balance in which there is a ____ of ____ of water excretion due to a failure of production, transport or release of ______ into the blood stream from the __________.
water
loss
ADH (Vasopressin)
Neurohypophysis
_Causes of Diabetes Insipidus _
_____ or ______ of _____ or _______; Commonly associated with tumors of the ______ which compress the _________.
Trauma
Disease
Pituitary
Hypothalamus
Adenohypophysis
Neurohypophysis
Diagnosis of Diabetes Insipidus
Imagery of the _____ with a positive finding of a tumor;
______ deprivation test - if animal is unable to produce ______ _______ urine as a water intake is restricted.
Pituitary
Water
More Concentrated
_Diabetes Insipidus _
Treatment: _____ or intranasal, oral or SQ injection of ________
Surgery
Desmopressin
Hypothalamus
Indirect effects on the endocrine system -
Production & Release of hypothalamic ______ _______ which either stimulate or inhibit the release of hormones from the _____ ______ ______.
releasing factors
Anterior Pituitary Gland
______________ (Cushing’s Disease) often accompanies tumors of the ______, which produce excess _________ hormone. One of the most common diseases of _____ aged and older dogs.
Hyperadrenocorticoidism
Adenohypophysis
Adrenocorticotropic
Middle
Symptoms of Hyperadrenocorticoidism (Cushing’s)
- _____ ______ (polyphagia - _____% show this sign)
- ____ ____ ___ (usually on the sides)
- ________ - Bloated abdomen and “potbelly” due to increase of fat in the abdomen and increased _____ size and stretching of abdominal wall (_____% have this symptom)
- ______ _____, ________ and sometimes lameness (excess ______ causes protein breakdown leading to muscle weakness)
Extreme Hunger - 80-95%
Poor Hair Coat
Obesity
Muscle Weakness, Lethargy
Cortisol
Treatment of Hyperadrenocoritcoidism (Cushing’s)
______ to remove _____ tumor
________ to control tumor growth
Medication - _____ or _____ - destroys the cortisol producing cells in the ______ _______
Surgery, Pituitary
Radiation
Lysodren or Mitotane
Adrenal Cortex
Hypothalamus
Control of the Autonomic Nervous System:
- _____ _____
- __________
- __________
- __________
Heart Rate
Vasoconstriction
Digestion
Sweating
What alterations have been observed in cattle with abscesses of the hypothalamus?
Alterations in cardiovascular function
Slowing of heart rate
The hypothalamus stimulates the ____ _____ which acts on _________ responses (e.g. Slowed heart rate)
Rostral Hypothalamus
Parasympathetic
The hypothalamus stimulates _____ _____ which acts on _____ responses (e.g. increased heart rate, vasoconstriction, etc.)
Caudal Hypothalamus
Sympathetic
The hypothalamus can control temperature regulation through the _____ and _____ hypothalamus.
Rostral & Caudal
The Rostral Hypothalamus is also known as the ___ ___ ______
Warm blood, antipyretic substances or impulses from heat receptors can cause _____, _____ and ____ which serve to _____ body temperature. Lesions cause ______ in dogs and other species.
Heat Loss Center
Panting
Vasodilation
Sweating
Reduce
Hyperthermia (fever)
The caudal hypothalamus is also known as the
_____ _____ _____
Cool blood, Pyrogenic substances or input from cold receptors causes _______ and ______, which serves to ______ body temperature. Lesions result in _____ and disturbances in _______ mechanisms.
Heat Conservation Center
Shivering & Vasoconstriction
Increase
Hypothermia
Sweating
Cattle with abscesses of the pituitary gland that effect the hypothalamus are often ___________.
Hypothermic
Hypothalamic Functions (6)
1.
2.
3.
4.
5.
- Direct effects on the Endocrine System
- Indirect effects on the Endocrine System
- Control of the Autonomic Nervous System
- Temperature Regulation
- Regulation of Food and Water Intake
The hypothalamus controls ______ ______ and appetite as well as water intake.
Lesions of the hypothalamus often cause abnormal ______ and ________.
Body Weight
Eating & Drinking
Lesions in the _________ Hypothalamus will cause an obese animal.
Ventromedial
Lesions in the _______ Hypothalamus will cause anorexia.
Lateral
