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Basic medicine: physiology
Published in Roy Palmer, Diana Wetherill, Medicine for Lawyers, 2020
There are two main sorts of gland in the body. Exocrine glands, such as the salivary and sweat glands, secrete their juice into a duct, whereas endocrine or ductless glands secrete hormones directly into the bloodstream. Hormones are proteins that act as chemical messengers, travelling in the blood to modulate the activity of a target organ that possesses the relevant hormone receptor. Endocrine tissue is found in many different organs, but it is concentrated in certain glands of which the pituitary is the most important. The pituitary gland is located inside the skull just below the brain and contains two main lobes. The anterior lobe secretes tropic hormones that control the activity of several other glands, including the thyroid, adrenal, breast, ovary and testis; it also secretes growth hormone, which affects the growth of many organs. The posterior pituitary secretes vasopressin and oxytocin, which act on the kidney and uterus, respectively. Pituitary insufficiency therefore has widespread effects. Pituitary secretion is controlled by a feedback system: rising blood levels of hormones secreted by the target organ in response to the pituitary hormone inhibit the secretion of that tropic hormone.
Summation of Basic Endocrine Data
Published in George H. Gass, Harold M. Kaplan, Handbook of Endocrinology, 2020
On the afferent aspect the hypothalamus receives its signals from various areas of the cerebral cortex and also from the lower brain and spinal cord. This releases the neurotransmitters, which link visceral and intellectual stimuli acting by way of the hypothalamus and from there to the anterior pituitary and finally to target organs. Stimulating the release of anterior lobe hormones is the major function of the hypothalamus in its relation to the anterior lobe of the pituitary. The hypothalamic control of releasing factors is a result of both humoral and neural afferent stimuli.
Endocrine system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
The pituitary gland lies in the sella turcica of the sphenoid bone (Fig. 10.2). The infundibulum (pituitary stalk) connects the gland to the hypothalamus of the brain, which lies above the optic chiasm and below the third cerebral ventricle and controls pituitary function by hormonal influence. The pituitary is divided functionally and anatomically into anterior and posterior lobes. Production of the two posterior lobe hormones (oxytocin and antidiuretic hormone [ADH]) is influenced by hormones sent down the axons of neurones in the pituitary stalk directly to that part of the gland. The anterior lobe produces seven hormones, and their control is by hormones released by the hypothalamus into the portal venous plexus that runs down the stalk to the anterior lobe, so that systemic blood levels of those hormones are very small indeed.
Efficacy and safety of follitropin alpha biosimilars compared to their reference product: a Meta-analysis
Published in Gynecological Endocrinology, 2021
Maria Cristina Budani, Stefania Fensore, Marco Di Marzio, Gian Mario Tiboni
Concerning the ovarian follicle development, follicle-stimulating hormone (FSH) is a gonadotrophic hormone produced by the anterior lobe of the pituitary gland [3]. FSH is a heterodimeric glycoprotein that consists of two distinct subunits, α and β. The α-subunit is common to all pituitary and placental glycoprotein hormones whereas the β-subunit is hormone-specific and the heterodimer confers biological activity [4]. Controlled ovarian stimulation (COS) for assisted reproductive technology (ART) is initiated and maintained through the exogenous administration of gonadotropins. Available exogenous FSH formulations include: highly purified human menopausal gonadotropin (hMG) obtained by extraction and purification from urine of menopausal women, highly purified human urinary FSH (u-hFSH) obtained by extraction and purification from human urine and recombinant FSH (r-FSH) obtained with recombinant technology [5].
Compressive trochlear nerve palsy caused by ischaemic stroke
Published in Clinical and Experimental Optometry, 2021
Visual acuity was 6/7.5 in the right eye and 6/7.5 in the left eye. Pupils were equal, reactive to light, without afferent pupillary defect. Extraocular motility testing revealed a subtle left hypertropia (two prism dioptres) that worsened in right gaze and with left head tilt, suggestive of a mild left CN IV palsy. Posterior pole photos confirmed increased excyclotorsion of the left eye, also consistent with a left CN IV palsy (Figure 2). The remainder of the patient’s ocular examination was within normal limits. The patient’s neuroimaging revealed ischaemic areas in the optic radiations (consistent with hemianopic visual field defects) and another ischaemic lesion of the anterior lobe of the rostral cerebellum that had compressed the left CN IV as it exited the dorsal midbrain, with mass effect resulting in compression of the left quadrigeminal cistern (Figures 3 and 4). The left trochlear nerve (arising from the nucleus in the dorsal right midbrain and exiting the brainstem posteriorly) passes through this space, and was also likely compressed.
A study on BOLD fMRI of the brain basic activities of MDD and the first-degree relatives
Published in International Journal of Psychiatry in Clinical Practice, 2020
Yulu Song, Xiaojun Shen, Xinnuan Mu, Ning Mao, Bin Wang
The conclusion that the ReHo (Regional Homogeneity) levels in right middle frontal gyrus, right precentral gyrus, right superior frontal gyrus, right anterior cingulate cortex, right insula, left putamen, left superior temporal gyrus, left middle temporal gyrus, left dorsal cingulate cortex of the depression group were significantly lower than those of the first-degree relative group (p <.05), which was shown in Table 2. The ReHo levels in left postcentral gyrus, left superior temporal gyrus, left middle temporal gyrus, left inferior frontal gyrus, left orbitofrontal cortex, left dorsal cingulate cortex, right precentral gyrus, right medial prefrontal cortex, right superior frontal gyrus, the middle frontal gyrus, the anterior cingulate cortex, right insular of MDD group were significantly lower than those of the control group (p<.05) (Figure 1). The ReHo levels in left anterior lobe of cerebellum, left middle temporal gyrus, left inferior frontal gyrus, left orbitofrontal cortex, left superior frontal gyrus, left dorsal cingulate cortex, left insula, right middle frontal gyrus, right anterior cingulate cortex of the first-degree relative group was significantly lower than those of the control group (p<.05) (Figure 2).