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22 Cards in this Set
- Front
- Back
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CNS & PNS |
The brain and spinal cord make up the central nervous system (CNS) Everything outside the brain and spinal cord is part of the peripheral nervous system (PNS) |
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Neuroglia (glial cells) |
Specialised cells that carry out the support activities for the nervous system, such as lining and covering cavities and supporting and protecting structures Examples of neuroglia: Astrocytes, oligodendrocytes, microglia, ependymal cells, Schwann cells, & satellite cells |
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Neurons |
Structures that nerve impulses travel along in the PNS to activate muscles or glands or deliver information. This is carried out by action potential. Cell body- responsible for cell metabolism Dendrites- receive information from the environment Axons- generates signals that are sent to other cells Axon terminals- located at end of axon transmit signals to receiving cells Synapses- spaces between axon terminal and dendrites of the receiving neuron |
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Action potential |
Polarised: A cell that is not stimulated or excited is a resting cell. It is more negative charge inside the cell compared to outside Depolarised: when cell is stimulated, Sodium ions travel in the cell across the membrane via ion channel. The ions are positively charged. Repolarisation: the sodium ion channels shut and other channels open to allow potassium ions to leave the cell. The cell becomes more negative inside & returning to rest |
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Impulse conduction |
Speed of conduction depends on: Presence of a Myelin sheath -lipid sheath (insulation) Allows action potential to skip down a nerve. Increases the speed of impulse transmission. -Diameter of the axon Larger the diameter of the axon, the faster the ions flow |
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Peripheral nervous system |
Sensory division: Input to CNS Motor division: Output of CNS to muscle & glands Control is both conscious and subconscious Eg. Moving arm (somatomotor)- conscious Eg. Flushing/ blushing (autonomic) - subconscious |
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Motor system |
Somatic nervous system controls skeletal muscle and voluntary movements Autonomic nervous system controls smooth muscle and cardiac muscle, along with several glands |
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Parasympathetic & sympathetic nervous system |
Autonomic system has 2 main branches: Parasympathetic system- controls normal body functioning including resting and digesting Sympathetic nervous system- controls the body’s alert system, including flight or fight response |
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Brain |
3 main sections: Cerebrum, cerebellum & brain stem The left half of the brain controls and received sensory information from the right side of the body. The right half of the brain controls the sensory information from the left side of the body. |
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Spinal cord |
3 distinct layers: - Dura mater: outer layer - Arachnoid mater: middle layer - Pia mater: innermost layer Epidural space is located between dura mater and vertebral column which is filled with fat and blood vessels |
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Neurotransmitter |
A chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate action potential |
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Disorders of nervous system |
Epilepsy, multiple sclerosis, Parkinson’s disease |
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Endocrine system |
Collects information and sends orders but it is a slower system and it’s effects last longer |
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Endocrine vs exocrine |
Endocrine glands secrete substances directly into the bloodstream eg. Pancreas, hypothalamus, thyroid Exocrine glands secrete substances that must exit the gland through a duct eg. Pancreas, sweat glands |
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Organs |
Hypothalamus Pituitary Pancreas Pineal gland |
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Effect of hormones on organs |
Hormone levels can be controlled in 3 ways: Neural control: control by the nervous system eg. Sympathetic control of adrenal gland Hormonal control: control by other hormones eg. Adrenal gland produces a stress hormone, the pituitary controls adrenal gland, the hypothalamus controls the pituitary. Humoral control: control by body fluids eg. Pancreas directly monitors blood glucose levels. When the levels deplete, the pancreas secrete hormones to correct blood sugar. |
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Hypothalamus |
Located in the brain. Controls temperature, appetite, fluid balance and pituitary gland. Hormones produced include: growth hormone, thyrotropin releasing hormone |
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Pituitary gland |
Located at the base of the brain. Functions: Control other endocrine glands respond to orders from the hypothalamus. 2 sections of pituitary gland: The posterior pituitary and anterior pituitary |
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Pancreas |
Located in upper abdomen, near stomach. An accessory organ of digestive system (exocrine function) Produces endocrine hormones - beta cells produce insulin - alpha cells produce glucagon |
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Negative feedback mechanism |
Counteracts change and reduce initial stimulus. Used to maintain appropriate hormone levels in the body. If hormone levels are too high, negative feedback will reduce secretion by endocrine organ responsible. Maintenance of stable blood glucose concentration is example of negative feedback |
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Positive feedback |
Increases magnitude of a change and causes characteristics to deviate further away from set point. Eg. Childbirth |
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Disorders of endocrine organs |
Hyperthyroidism, diabetes, crushing disease |
