Limbic System & Hypothalamus Flashcards by Blake Hollowoa

In humans, the _____________ has a diminished importance compared to other vertebrates.

Olfactory

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Olfactory receptors consist of neurons embedded in _____________ cells.

Epithelial cells

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(T/F) You keep the same set of olfactory receptors throughout your entire life.

False. Olfactory receptors are replaced throughout one’s lifetime.

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Around ___ fiber bundles/side enter the skull via the cribriform plate of the ethmoid bone and terminate in the olfactory bulb .

20 fiber bundles/side

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_________ cells are the principal neurons of the olfactory bulb.

Mitral cells

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The axons of ________ cells constitute the olfactory tract.

Mitral cells

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The olfactory tract follows the ventral surface of the frontal lobe and terminates in the ________________ and ______________ of the temporal lobe.

Anterior perforated substance and pyriform

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Most axons within the olfactory system follow the lateral olfactory stria to end in the ipsilateral cortex near the ___________.

Uncus

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(T/F) Olfactory tracts terminate uncrossed.

True.

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(T/F) The olfactory tract projects first to the thalamus and then to the cerebral cortices.

False. The olfactory system terminates directly in the cortex.

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Information from one olfactory bulb may be sent to the other via the ___________________ and the _________________.

Medial olfactory stria and the anterior commissure

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___________ is used to refer to the leakage of CSF from the nose, typically following a fracture to the floor of the anterior cranial fossa which involves the cribriform plate.

Rhinorrhea

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___________ are tumors that may impinge upon the olfactory tracts after arising from the floor of the anterior cranial fossa. This is usually a unilateral impairment and each nostril must be tested for anosmia.

Meningiomas

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Epileptic discharges termed ______________ are characterized by olfactory hallucinations, usually of a disagreeable or offensive type such as the smell of burning rubber. They may also result in involuntary movements of the lips and tongue.

Uncinate fits

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Uncinate fits result from compression of the _______________.

Temporal cortex

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The limbic lobe consists of the:

Cingulate gyrus
Parahippocampal gyrus
Hippocampus
Amygdala

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The ______________ occupies the floor of the temporal horn of the lateral ventricle. It also bears resemblance to a C-shape in the sagittal plane and a seahorse-shape in the coronal plane.

Hippocampus

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The major outflow from the hippocampal formation is via a large fiber bundle that terminates in the mammillary bodies, known as the ___________.

Fornix

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The _____________ receives a considerable amount of input from the amygdala via the stria terminalis and diagonal band.

Septal region (septum)

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The major limbic structures within the hypothalamus are the _______________.

Mammillary bodies

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The mammillary bodies receive a great deal of their input from the (ipsilateral/contralateral) fornix.

Ipsilateral fornix

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The mammillary bodies have a major efferent tract termed the ___________________ tract.

Mammillothalamic tract

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The mammillothalamic tract terminates in the __________ thalamic nucleus.

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(T/F) The olfactory system projects to the amygdala without making use of the thalamus.

True.

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The major pathway to and from the amygdala is the \_\_\_\_\_\_\_\_\_\_\_\_\_\_. It connects the amygdala with the septal region and hypothalamus.

Stria terminalis

The _____________ nuclei are involved with integrating information concerned with reproduction.

Habenular nuclei

The septum projects to the habenular nuclei via the \_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Stria medullaris

One of the main functions of the hippocampus is the conversion of ____________ to \_\_\_\_\_\_\_\_\_\_\_\_\_.

Short-term memory to long-term memory

(T/F) Bilateral lesions of small areas of the hippocampus are associated with profound impairment of recent events. Long-term memories are especially affected in these lesions.

False. Bilateral lesions of **large** areas of the hippocampus are associated with the profound impairment of recent events. Long-term memories are usually **unimpaired.**

Because the hippocampus is part of the limbic system, ____________ are associated with memories.

Emotions

\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is a psychosis thought to derive from a thiamine (B1) deficiency associated with chronic alcoholism. The lesions **always involve the mammillary bodies**, **hippocampus**, and **dorsomedial thalamic nuclei**. These patients can form no new memories.

Korsakoff's syndrome

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is a syndrome that results from **massive** bilateral lesions to the temporal lobe, including the amygdala, hippocampus, and parahippocampal gyrus. Patients have an **absence of** **emotional responses** so that fear, rage, and aggression cease to be displayed. Patients also exhibit a compulsion to be overly attentive to all sensory stimuli, as well as **hypersexuality** and **visual agnosia** in which objects are not recognized visually.

Klüver-Bucy syndrome

Electrical stimulation of the amygdala causes \_\_\_\_\_\_\_\_\_, \_\_\_\_\_\_\_\_\_, and \_\_\_\_\_\_\_\_\_\_\_\_\_\_.

* Fear * Anxiety * Eating behavior

Stimulation of the __________ cortex will cause olfactory hallucinations.

Entorhinal (temporal lobe)

Areas of the septum and rostral hypothalamus can be described as \_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Pleasure centers

The _____________ has an essential role in regulating almost every autonomic reaction.

Hypothalamus

The hypothalamus controls (sympathetic/parasympathetic/both sympathetic and parasympathetic) responses.

Both sympathetic and parasympathetic

Parasympathetic responses may be evoked by stimulation of sites located in the (anterior/posterior) hypothalamic areas.

Sympathetic responses may be evoked by stimulation of sites located in the (anterior/posterior) hypothalamic areas.

Posterior

The hypothalamus is intimately associated with the ________ gland.

Pituitary

The hypothalamus is connected to the pituitary gland via the ________________ tract.

Hypothalamo-hypophyseal tract

The hypothalamus regulates the activity of the anterior pituitary gland by producing stimulatory or inhibitory factors that are released into the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Hypophyseal portal system

The anterior boundary of the hypothalamus is the \_\_\_\_\_\_\_\_\_\_\_\_\_.

Lamina terminalis

The posterior boundary of the hypothalamus is the \_\_\_\_\_\_\_\_\_\_\_\_\_.

Posterior edge of the mammillary body

The dorsal boundary of the hypothalamus is the \_\_\_\_\_\_\_\_\_\_\_\_\_.

Sulcus limitans

The lateral boundary of the hypothalamus is the \_\_\_\_\_\_\_\_\_\_\_\_\_.

Fibers of the subthalamus and optic tracts

The ventral boundary of the hypothalamus is the \_\_\_\_\_\_\_\_\_\_\_\_\_.

Subarachnoid space

What are the three regions of the hypothalamus?

* Supraoptic or anterior * Tuberal or middle * Mammillary or posterior

Hormones of the anterior pituitary are released into the hypophyseal portal system that then coalesces and drains into the \_\_\_\_\_\_\_\_\_\_\_\_\_\_, gaining access to the general circulation.

Cavernous sinus

The (posterior/anterior) hypothalamus controls the body's heat loss function. Lesions of this region may cause dysregulation of body temperature and result in hyperthermia.

Anterior hypothalamus

What hormones are released by the arcuate and paraventricular nuclei of the hypothalamus in order to regulate activity of the pituitary?

* Corticoptropin-releasing hormone (CRH or CRF) * Growth-hormone releasing hormone (GHRH or GHRF) * Thyrotropin-releasing hormone (TRH or TRF) * Somatostatin * Dopamine

Destruction of the _______________ nucleus of the hypothalamus results in disruption of circadian rhythm of hormone release and sexual cycles.

Suprachiasmatic nucleus

The (posterior/anterior) hypothalamus is responsible for the body's heat conservation and serves in maintenance of the "set point" for body temperature.

Posterior

(T/F) The anterior hypothalamus can increase body temperature by decreasing sweating and blood flow to the skin and by causing shivering.

False. The **posterior** thalamus is responsible for increasing body temperature and avoiding hypothermia.

The condition known as ______________ results if the anterior and posterior hypothalamus are both destroyed, causing body temperature to follow the temperature of the environment.

Poikilothermia

The _______________ and ______________ hypothalamic nuclei are involved in the regulation of food intake.

**Medial** - **Satiety**, emotion, endocrine (Ar) **Lateral** - **Hunger**/**feeding**

The ______________ hypothalamic nucleus is a **satiety** center. Stimulation of this center causes hypophagia and a decrease in appetite.

**Medial**

The ______________ hypothalamic nucleus is a **feeding** and **hunger** center. Stimulation of this center causes hyperphagia and a marked increase in appetite.

**Lateral**

The ______________ and _______________ nuclei are crucial to the appropriate control of fluid balance and blood pressure regulation via secretion of vasopressin (ADH).

Supraoptic nucleus (SON) and paraventricular nucleus (PVN)

A clinical state characterized by polyuria and polydipsia (excessive thirst) that can be brought about by destruction of the **supraoptic** and **periventricular nuclei** of the **hypothalamus** is known as \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Diabetes insipidus

The (ventral/dorsal) longitudinal fasciculus connects the hypothalamus with the brainstem and spinal cord.

Dorsal longitudinal fasciculus

\_\_\_\_\_\_\_\_\_\_\_\_ is the arrest of menses.

Amenorrhea

Amenorrhea may be caused by insufficient release of _______________ or \_\_\_\_\_\_\_\_\_\_\_\_\_.

Luteinizing-hormone releasing hormone (LHRH) or follicle stimulating hormone (FSH)

\_\_\_\_\_\_\_\_\_\_\_ may be caused by a lesion of the anterior hypothalamic nuclei, the tuberal hypothalamus, or the pituitary gland. It is associated with dysregulation of follicle stimulating hormone and luteinizing-hormone releasing hormone.

Amenorrhea

\_\_\_\_\_\_\_\_\_\_\_ is the excessive or spontaneous production of milk.

Galactorrhea

Galactorrhea is involved with an abnormality of the hormones ____________ and \_\_\_\_\_\_\_\_\_\_\_\_\_\_.

Prolactin and oxytocin

\_\_\_\_\_\_\_\_\_\_\_\_\_\_ may be caused by a lesion of the arcuate nucleus, the anterior hypothalamus, median eminence, or pituitary stalk. It is associated with dysregulation of prolactin and oxytocin.

Galactorrhea

(T/F) Visual clues, such as bitemporal hemianopsia, may hint at the presence of a tumor located in the pituitary. The optic nucleus or optic chiasm often become compressed in these tumors, generating the visual abnormalities.

True.

\_\_\_\_\_\_\_\_\_\_\_\_\_ is a condition caused by hypersecretion of pituitary growth hormone after maturity and is characterized by the enlargement of the extremities of the skeleton.

Acromegaly

Acromegaly may be caused by lesions in the (anterior/posterior) pituitary.

A disease marked by protein depletion, no change in cortisol levels between day and night, abnormal accumulation of fat in face, neck, and trunk, kyphosis, amenorrhea, hypertension, and muscular weakness is known as \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. This condition is caused by the **hypersecretion of** **adrenocorticotropic hormone** (**ACTH**). This condition is most likely caused by the presence of a pituitary tumor.

Cushing's disease