Locomotion and Regulation Skeletal System Functions of bones: 1.support and protection of the body 2.anchorage sites for muscles 3.leverage for movement 4.production of blood cells in the bone marrow Cartilage provides support, flexibility, and cushions joints Skull Humerus Radius Ulna Femur Tibia Fibula Vertebrae Sternum Ribs Phalanges Pelvis Muscular System Three types of muscles 1.smooth (visceral): involuntary 2.cardiac: heart muscle, also involuntary 3.skeletal (striated): voluntary Skeletal muscles pull on bones to move joints Extensor muscles extend (straighten) joints Flexor muscles flex (bend) joints Tendons: connect muscles to bones Ligaments: connect bones to bones Diseases Arthritis: inflammation of the joints Tendonitis: inflammation of the tendons Nervous System Nerves send signals through the body Signals = impulses The nervous system has two parts: 1.Central nervous system (CNS): brain and spinal cord 2.Peripheral nervous system (PNS): all nerves outside the CNS The PNS is divided into two parts: 1.Somatic nervous system: voluntary 2.Autonomic nervous system: involuntary Neurons Nerves are bundles of cells called neurons Impulses are passed from neuron to neuron using chemicals called neurotransmitters Very fast Sensory neurons send impulses from body parts to the CNS Motor neurons send impulses from the CNS to the muscles Interneurons connect the sensory neurons to the motor neurons Dendrites Nucleus Cell body Axon Myelin sheath Axon terminals Impulses enter the neuron at the dendrites The impulse travels down the axon The myelin sheath insulates the axon Just like rubber insulates wires When the impulse reaches the axon terminals, neurotransmitters are released Neurotransmitters carry the impulse to the dendrites of the next neuron Reflex Arc A reflex arc is a pathway over which impulses travel Receptors in the skin sensory neurons interneurons in the spinal cord motor neuron effector (muscle) Ex: when you touch a hot stove, the heat signal travels to the neurons in the spinal cord, and a message to move your hand gets relayed back to your muscles The Brain The brain is a large mass of neurons It is responsible for controlling and coordinating most of the activities of the body The brain has three main parts: 1.Cerebrum: controls voluntary activities, memory, thinking, and reasoning 2.Cerebellum: coordinates muscle movements and helps maintain balance 3.Medulla: controls heartbeat, breathing, blood pressure, and peristalsis Medulla Cerebellum Cerebrum Diseases Meningitis: inflammation of the membranes that surround the brain and spinal cord Stroke: when a blood clot blocks a blood vessel in the brain Causes cells to die Endocrine System Composed of mostly of glands Glands release hormones into the blood Hormones cause changes in certain cells Slower than the nervous system Hypothalamus Pituitary gland Thyroid Parathyroid Thymus Adrenal gland Pancreas Testes Ovaries Glands Hypothalamus: part of the brain that controls the pituitary gland Pituitary gland: master gland that regulates many body parts Makes growth-stimulating hormone (GSH), which causes the bones to grow Thyroid-stimulating hormone (TSH) makes the thyroid make its hormone Follicle-stimulating hormone (FSH) acts on the ovaries and testes Thyroid: regulates the rate of metabolism using the hormone thyroxine Parathyroid: regulates the use of calcium using the hormone parathormone Thymus: necessary for the immune system Adrenal glands: make adrenaline for the fight or flight response Islets of Langerhans: cells in the pancreas that control blood sugar levels Insulin lowers blood sugar Glucagon raises blood sugar Testes: make testosterone for the development of male secondary characteristics Ovaries: make estrogen for the development of female secondary characteristics Hormone Action Hormones only affect certain cells All cells in the body have protein molecules on the surface of the cell membrane These are called receptors Each type of cell has its own receptor shape Hormones can only affect cells whose receptors match the shape of that hormone Just like enzymes and substrates and antibodies and antigens Feedback In negative feedback, the release of one hormone affects the production of another hormone Ex: After a meal, blood sugar is high and insulin is produced. This turns off glucagon production. Ex: After not eating for a while, blood sugar is low and glucagon is produced. This turns off insulin production. Negative feedback also works to maintain other aspects of homeostasis Ex: when your temperature drops too low, your muscles contract rapidly (shivering) to generate heat until your temperature goes back to normal Ex: when your temperature gets too high, you sweat so that when the sweat evaporates, the excess heat is removed from your skin Diabetes The body cannot make any insulin, or does not make enough Blood sugar remains high, instead of going into the cells to be turned into energy Type 1 diabetes occurs when the immune system destroys the insulin-producing cells Autoimmune disease This is usually diagnosed in childhood and is treated with insulin injections Type 2 diabetes occurs when the pancreas no longer makes enough insulin or the body cells cannot react to insulin May be caused by obesity, lack of exercise, or genetics Can be managed with diet and medication Nervous Vs. Endocrine Both systems help maintain homeostasis The nervous system uses neurotransmitters The endocrine system uses hormones The nervous system is fast and responses are short The endocrine system is slow and responses are long-lasting