NSCI 110 1st Edition Lecture 16 Outline of Last Lecture I. Drugs’ effects may sum if absorbed by the body at the same timea. Produce IPSPs or EPSPsII. Dependency, sensitization, learning, and other variables such as basal metabolic rate and sex alter a drug’s effects on an individualIII. A neurohormone is any hormone produced and released by neuroendocrine/neurosecretory cells into the blooda. A feedback system referred to as the HPA axis is responsible for the stress response and includes a fast and slow-acting pathwayOutline of Current Lecture I. Nuclei located in the hypothalamus extend to either the posterior or anterior pituitary glanda. Two neurohormones, oxytocin and vasopressin, are crucial to this systemII. Traumatic brain injuries are an extremely common source of injurya. Include lesions and zone of trauma, where cell death may occurb. Astrocytes and microglia are involved in responses to injury Current Lecture- Posterior pituitary glando Axons of two nuclei extend to the gland, carrying vesicles with the hormone and causing a release of hormones into the vascular systemo Two neurohormones crucial to this system (controlled by two nuclei in the hypothalamus) Oxytocin through the paraventricular nucleus (superior)- Involved in lactation, uterine contraction, parental behavior, sexual behavior, social bonding, aggression Vasopressin through the supraoptic nucleus (inferior) magnocellular- Involved in regulating blood pressureo As blood pressure decreases, it signals the nucleus to retain more water and constrict blood vessels- Also known as antidiuretic hormone (ADH)o Involved in kidney function, controlling salt concentration- Induces drinking behavior These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.TRAUMATIC BRAIN INJURY- Each year in the US…o Over 2 million people experience a traumatic brain injury of some sorto 675,000-800,000 injuries are seen in the ERo 500,000+ patients are hospitalizedo Due to incidents by firearms, vehicle accidents, falls, ect.- Trauma injurieso Open vs. closed head injurieso Rotation of head Cranium is suppressed and vascular supply may be compromisedo Reboundo Primary impact Depression Avulsion (hemorrhage) Shearing and stretching (portion of the brain hits the skull first and is compressed, causing axon fibers to stretch and may disconnect from cell bodies)- Diffuse axonal injury- Vessels are subject to these forces as well Contusions (bruising) Lacerations - Types of lesionso A coup lesion occurs at the point of impact The zone of trauma will be greatest at the point of impacto A contrecoup injury occurs where the point of impact is at the opposite side of the brain Falx cerebri or tentorium cerebelli may reduce magnitude of injury by absorbing some force of the impact o A coup-contrecoup injury involves damage to both sides- At the zone of trauma (the point where injury is greatest)o At the central zone scar tissue begins to form by the action of astrocytes, usually within hours Astrocytes proliferate and migrate to this site Vacuole filled with CSF forms (the edges are scar tissue)o Microglia migrate to the site and attempt to stop any further accumulation of debris by performing phagocytosis “Cleaning up” the siteo Surrounding cells may return to function but overall structure’s function may be compromisedo As you travel away from central zone, cells begin to fight for nutrients and survival Some may carry out apoptosis Astrocytes migrate here and provide nutrientso As you travel even further, cells appear normal but still may not function Cells are in “shock”o In outer regions cells are intact and may function normally as long as essential neural connections are
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