Homeostasis

• The circulatory and lymphatic systems transport materials throughout the body.
• The placenta contains blood vessels from both the mother and fetus.
• The placenta nourishes the developing embryo by the umbilical cord.
• The circulatory, lymphatic and immune systems protect the body against disease and foreign substances.
• The digestive, respiratory and excretory systems add or remove substances from the blood.
• The integumentary system includes the skin, nails, hair and glands, and communicates with the brain and spinal cord via nerve fibres.
• The muscular, skeletal and integumentary system protect and support the internal environment of the body.
• The nervous system allows the body to respond to internal and external stimuli.
• The endocrine system consists of hormonal glands.
• The reproductive system produces and transports gametes and produces sex hormones.
• Homeostasis is the tendency of the body to maintain a relatively constant internal environment.
• Feedback systems are a cycle of events in which a variable (body temperature, blood glucose level, or blood pH) is continually monitored, assessed, and adjusted.
• Negative feedback systems work to reverse a change detected in a variable and bring it back within a normal range.
• Positive feedback systems tend to strengthen or increase a change in a variable, and have a definitive cut-off point.
• The central nervous system includes the brain, spinal cord, nerves, and sensory organs.
• Glial cells were discovered by Rudolf Virchow.
• Excitatory neurotransmitters stimulate the brain, while inhibitory neurotransmitters calm the brain.
• Schwann cells are named after Theodore Schwann.
• Main parts of the endocrine system include glands, hormones, bloodstream, receptors.
• The function of glial cells depends on the type of glial cell.
• “all or nothing” rule states that if the stimulus reaches the threshold, an impulse will occur, if not, the impulse will not occur.
• Neuron Communication involves dendrites picking up electrochemical signals from other neurons.
• Endocrine System functions as a series of glands that release hormones into the bloodstream to help control your organs.
• A nerve impulse is an electrical transmission across neurons.
• Threshold is the minimum level of stimulus that must be reached in order for an impulse to occur.
• Hormone action can be categorized as Steroid Hormone or Amino Acid Hormone, depending on what the hormone is made out of.
• Neurotransmitters are brain chemicals that communicate information throughout our brain and body.
• Nodes of Ranvier are named after French pathologist Louis Antoine Ranvier.
• Interneurons carry impulses between sensory and motor neurons.
• Hormones are used to regulate metabolism, growth and development, sexual functions, sleep, mood, stress, and response to injury.
• The impulse within neurons always travels from the dendrite to the axon.
• Glial cells surround neurons to hold them in place, supply neurons with oxygen and nutrients, insulate neurons so they aren’t directly touching, remove dead neurons and destroying foreign invaders.
• Dendrites are projections of the cell body that can receive electrical stimulation from other neurons via synapses.
• Nerve impulses begin when a neuron is stimulated by another neuron or its environment.
• Examples of glands include Adrenal glands, Pineal gland, Thyroid, Pancreas, Ovary, Testis.
• Resting potential is when the inside of a neuron is negative compared to the outside.
• Action potential is when the inside of a neuron is positive compared to the outside.
• Hormones attach to receptors found on the plasma of the cell membrane or nuclei.
• The chemicals produced by glands are called hormones, which are specific to certain target tissues.
• The myelin sheath acts as an insulator which helps speed up the rate of impulses.