Experiment 5 Anesthesia and Small Mammal Surgery There are 4 routes available for administration of injectable drugs Subcutaneously SC Under the skin Slowest mode of action Mostly used for vaccinations Intramuscularly IM Intraperitoneally IP Intravaneously IV In the gut Fastest mode of action Calculating proper anesthesia dosage Anesthesia falls into 3 different categories Weight in kg x dosage x reciprocal of drug concentration dose in mL Gaseous Volatile Easy to control Very few side effects Inhalable i e Nitric oxide laughing gas Liquid at room temperature but readily evaporates Inhaled and liquid soluble i e ether and halothane Passes into blood and cells easily Slow induction time Most popular surgical anesthesia Requires hella careful calculation of dose Cannot be removed once injected i e barbituates ketamine and carbamates Injectable carbamate used in this lab is Urethane Urethane is hepatotoxic and carcinogenic We use it because it has the highest margin of error I m thinking the first one is toxic to your liver Injectable Stages of anesthesia after injection Analgesia Little to no feeling of pain but not surgery ready Begins with administration and ends with loss of consciousness Unconcious but may experience thrashing out increased muscle Excitement and Delirium tone rapid breathing and involuntary eye movements Surgical anesthesia Patient feels no pain Regular breathing Relaxed muscle tone Patient s pedal and corneal reflexes must be checked to ensure this stage is active Respiratory and Circulatory Paralysis Can lead to death Thin dose line between third and fourth stages Questions 1 What animal are you working on today The animal in the picture is a rabbit but it says we will work on a rat but it s really a rabbit 2 What is the first surgery you are going to do today 3 What plane of anesthesia will your animal be in when you begin Tracheotomy surgery Surgical anesthesia 4 You are a given an animal that weighs 175g In order to properly administer anesthesia you must properly calculate the dose The drug concentration is 35g 100mL and your animal requires 2 0g drug kg What volume do you need to administer 175g 0 175kg 2 0g drug kg 100mL 35g 1mL 5 Why perform a venous cannulation It is the fastest form of anesthesia 6 In a full system Ach is a neurotransmitter for which branch of the autonomic nervous system Parasympathetic and Sympathetic Gaseous 7 Nitric oxide is an example of what kind of anesthetic Experiment 6 Blood Pressure Blood Pressure the body The outward force of blood against artery walls as it is pushed through BP CO TPR Two major physiological components Cardiac output unit of time L min Amount of blood pumped by the ventricle of the heart per given More blood pumped higher the blood pressure CO HR SV SV stroke volume the amount of blood pumped by each ventricle in 1 heart beat Peripheral resistance How difficult it is for the blood to travel through blood vessels Smaller the diameter of blood vessel the higher the resistance Blood vessel diameter controlled by vascular smooth muscle under primary control of sympathetic nervous system Blood Pressure Measurements have two components Systolic Pressure contracted and pushed blood into the arteries Function of cardiac output Pressure in the arteries at the point when the ventricles have High value After the ventricles have finished contracting and are relaxed Diastolic Pressure Arterial blood pressure drops Low value Function of peripheral resistance Medulla Oblongata controls blood pressure Contains two groups of neurons Vasomotor center VMC vascular smooth muscle Signals sent along sympathetic motor pathways to the heart and Stimulate 1 receptors on heart Stimulate Alpha 1 receptors on vascular smooth muscle Induces vasoconstriction and increase the peripheral resistance of blood vessels Vagal Center VC Sympathetic signals also stimulate the adrenal medulla causing the release of epinephrine into the blood stream that binds to alpha receptors and increases TPR Increase in blood pressure as a result of sympathetic simulation Sympathetic pathway is considered excitatory Sends signals through the parasympathetic motor pathways through cranial nerve X Vagus nerve Primary target is the pacemaker of the heart where stimulation of muscarinic receptors decreases heart rate cardiac output and blood pressure There is no innervation from the vagal center on the vasculature VC is also in the medulla oblongata Both VMC and VC are inhibitory towards each other When one fires the other is inhibited Negative feedback mechanism Blood pressure control can be Long term Via actions of the kidneys and associated hormones Short term Via neural control This lab demonstrates neural control Neural Control Baroreceptor Reflex Most commonly used mechanism of neural control Baroreceptors Pressure sensing receptors responds to the stretching of the blood vessels Located in the aortic arch and bifurcation of the common carotids Fire at baseline rate when BP is normal change frequency when BP changes Increase when BP goes up and vice versa Sensitive to stretching of walls by incoming blood flow Increased BP Afferent signals sent along vagus and glossopharyngeal nerve to the medulla They stimulate the VC and inhibit the VMC VC stimulation causes a decrease in HR which decreases cardiac output and BP Decreased BP Reflex fires at a much lower frequency VMC stimulated VC inhibited Increases CO and PR which increases BP Chemoreceptors Reflex Chemoreceptors Questions High waste chemicals Found in same place as baroreceptors Sense waste chemicals in blood i e CO2 and Hydrogen ions Cause a stimulation of VMC Inhibition of VC Increased BP Increases circulatory time to facilitate the removal of waste CO TPR Alpha 1 Beta 1 and M 2 are their respective effects What is the equation for BP What autonomic receptors are available to us in this preparation What are two medullary centers that control blood pressure and what What is the effect of adding Ach after atropine What two receptor types help monitor BP What is the 1st thing surgically you need to do when you get your Baroreceptors and chemoreceptors rabbit Tracheotomy Ketamine belongs to which of the 3 main anesthetic classes Injectable anesthetic Experiment 7 Cardiac Physiology Cardiac muscle is myogenic Autorhythmic The frog heart is three chambered with 2 atria and 1 ventricle The Sinus venosus is the pacemaker of the frog heart analogous to the The Sinus venosus has two cell types They