Lab

• The nervous system is the master control and communication system of the body, regulating homeostasis and environment (internal and external).
• The nervous system is composed of organs: brain, spinal cords, ganglia.
• The nervous system has three functions: sensory (nerve impulses), integration, and motor.
• Sensory input is converted into electrical signals called nerve impulses that are transmitted to the brain.
• Nerve impulses travel from the brain to the proper response, which is determined by efferent neurons.
• The process by which the nervous system processes and interprets sensory information is called integration.
• Motor responses are based on the sensory input and integration, with the nervous system responding by sending signals to muscles, causing them to contract, or to glands, causing them to produce secretions.
• Neurons are the "conducting" cells that transmit impulses and the structural unit of the nervous system.
• Atrial Diastole, also called ventricular filling, occurs when the heart is relaxed, causing AV valves to open and 80 percent of the blood to flow into the ventricles, leaving 20 percent of blood in the atria.
• Isovolumetric relaxation occurs when the ventricles relax, causing the pressure to drop and SV valves to close to prevent backflow to the ventricles.
• Ideal blood pressure ranges from 100 to 140 in systolic and 90 to 60 in diastolic.
• An arterial pulse is the alternating expansion and recoil of an artery that occurs with each beat of the left ventricle, creating pressure/pulse points.
• You can feel a pulse in any artery lying close to the body surface by compressing the artery against firm tissue.
• Atrial Systole occurs when the atria contract to release 20 percent of blood.
• Blood pressure is the pressure the blood exerts against the inner wall of the blood vessels, and it is the force that keeps blood circulating continuously even between heartbeats.
• A normal blood pressure range is 120/80.
• Isovolumetric contraction occurs when there is pressure in the ventricles, causing AV valves to close to prevent backflow in the atria.
• Ventricular systole, contraction, or ejection occurs when the ventricles contract, pushing the blood out of the heart into the lungs and other parts of the body.
• Neurons have no centrioles and are highly specialized.
• Neurons are classified as afferent, efferent, or interneurons according to the direction in which they transmit impulses relative to the central nervous system.
• Corticospinal and other descending pathways that influence the reflex arc are usually interrupted due to a suprasegmental lesion, a lesion above the level of the spinal reflex pathways.
• The sensory system receives and processes information that generates an individual's awareness of their environment.
• Sensations can be categorized into general senses such as touch and pain, and special senses like smell, taste, sight, and hearing.
• The extrinsic eye muscles include the lateral rectus, lateral medial, superior rectus, inferior oblique, and superior oblique.
• The eyelids protect the eye anteriorly and meet at the medial and lateral corners of the eye, the medial commissure (canthus) and lateral commissure (canthus).
• The sensory system consists of the general senses which include touch, pain, and the special senses which include smell, taste, sight, and hearing.
• The conjunctiva is a delicate membrane that lines the eyelids and covers part of the outer surface of the eyeball, ending at the edge of the transparent cornea by fusing with the corneal epithelium.
• Eyelashes project from the border of each eyelid and contain ciliary glands, which are modified sweat glands, and their ducts open at the eyelash follicles.
• The sebaceous glands, also known as tarsal glands, produce an oily secretion that lubricates the eye.
• Tears flush across the eyeball into the lacrimal canaliculi medially, then into the lacrimal sac, and finally into the nasolacrimal duct, which empties into the inferior meatus of the nasal cavity.
• The lacrimal apparatus consists of the lacrimal gland and a number of ducts that drain lacrimal secretions into the nasal cavity, located above the lateral end of each eye.
• Various sensory perceptions then influence voluntary and involuntary motor activity to facilitate interaction with the world.
• The eyeball is a hollow sphere with layers: humors (fluids) and lens (main focusing).
• The palpebral fissure is the eye space between the eyelids.
• Sensory information is processed via cranial nerves and differs from the pathway utilized in processing general senses.
• Afferent neurons carry impulses from peripheral sense receptors to the CNS and have long dendrites, short axons.
• Efferent neurons transmit impulses from the CNS to effector organs such as muscles and glands and have short dendrites, long axons.
• Interneurons are located entirely within the CNS and form the connecting link between the afferent and efferent neurons, with short dendrites, either long/short axons.
• Neuroglia cells are nonconductive and provide a support system for the neurons, capable of mitosis, and do not conduct nerve impulses but instead, they support, nourish, and protect the neurons.
• The anatomical pathway of a reflex consists of an afferent nerve, usually one or more interneurons within the central nervous system, and an efferent nerve.