KEY CONCEPTS:
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Neurons - carry signals or impulses. Neurons Nerve impulse impulse - electrochemical signal moving signal moving along a neuron. Synapse - space between neurons Stimulus Stimulus - any factor in the environment that influences behavior . Response - reaction to reaction to a condition or stimulus.(An organism must be able to
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respond to a stimulus in order to survive.) Reaction time time - length of time between application of a stimulus and stimulus and detection of a
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response When a receptor such as an organ perceives a stimulus, the impulse is sent
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to the brain by brain by the sensory neurons, neurons, which then transmit information from one nerve cell to another. As the message reaches the brain, it processes the information and commands an effector such as a muscle or an organ to respond respond.. The message message co comi ming ng from the the brain brain is sent sent through through the motor •
neurons. Hormones – chemicals chemicals that that secreted secreted by the glands glands of endocrine system that controls various body processes. This control system usually brings about slow changes in the body because chemical messengers move messengers move more slowly than nerve impulses. impulses. The The mao maorr glan glands ds in the the body body are the the pituitary pituitary thyroi! thyroi! parathyroi! parathyroi!
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thymus a!renal pancreas ovaries an! testes" Hormones – Hormones – regulate ! balance the functioning or organs" impacts growth !
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appearance" determines whether or not people develop disorders. Hormonal im#alance im#alance - An increase or decrease in hormonal levels le vels Pituitary glan! glan! - controls the functions functions of of both the testes and the ovaries. ovaries.
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$ %ain &ivisions o' Nervous Systems:
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#entral $ervous %ystem (#$%) and
&eripheral $ervous %ystem (&$%). (&$% ). •
The #entral #entral $ervous %ystem %ystem (#$%) (#$%) - main 'processing 'processing center. center. *ain &arts+ &arts+ rain ! %pinal #ord.
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The &eripheral $ervous %ystem (&$%) contains all nerves that etend outside the brain and spinal cord. t has two main divisions, which are the %omatic $ervous %ystem and the Autonomic $ervous %ystem.
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The basic unit of the nervous system is the nerve cell. $erve cells are called neurons. $eurons have dendrites and aons that aid in transmitting message.
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$euron $eurons s have have the special special abilit ability y to carry carry signal signals s or impuls impulses. es. A nerve impuls impulse e is an electrochemical gradient moving along a neuron. The space between neurons is called synapse. A stimulus is any factor in the environment that may induce a nerve impulse that initiates physiological and behavioural changes. A response is a reaction to a condition or stimulus. To survive, an organism must be able to respond to a stimulus. /eaction time is the length of time between application of a stimulus and detection of a response.
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When a receptor such as an organ perceives a stimulus, the impulse is sent to the brain by the sensory sensory neurons, neurons, transm transmitt itting ing inform informati ation on from from one nerve nerve cell cell to anothe another. r. As the message reaches the brain, it processes the information and commands an effector such as a muscle or an organ to respond. The message coming from the brain is sent through the motor neurons.
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The 0ndocrine %ystem consists of glands that secrete chemicals called hormones which control various body processes. This control system usually brings about slow changes in the body because chemical messengers move more slowly than nerve impulses. The maor glands in the body are the pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, ovaries and testis.
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1ormon 1ormones es affect affect various various process processes es in the body as they regulate regulate and balance balance the func functi tion onin ing g of orga organs, ns, tissu tissues, es, and cell cells. s. 1orm 1ormon ones es grea greatly tly infl influe uence nce growt growth, h, appearance, emotions, and reproductive functions. These chemicals play an essential role in the occurrence of disorders such as diabetes, thyroid disease, growth and2or seual dysfunction. 1ormones act in very small amounts. An increase or decrease in the said amount may result in a body disorder due to hormonal imbalance.
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The /eproductive %ystem is a collection of organs in an organism that function together for seual reproduction. The male reproductive organs are the penis, the testicles, the epididymis, the vas deferens, and the prostate gland. The female reproductive organs are the vagina, uterus (womb), 3allopian tubes, and ovaries.
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1ormon 1ormones es play play an import important ant role in both both male male and female female reprodu reproduct ctive ive syste systems. ms. The pituitary gland controls the functions of both the testes and the ovaries. These hormones 4eep the reproductive system properly functioning.
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1ormones secreted by the ovaries and a small gland in the brain called the pituitary gland control the menstrual cycle.
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3eed 3eedba bac4 c4 mecha mechani nism sm is the the proce process ss throu through gh which which the the leve levell of one one subst substan ance ce influences the level of another substance. A negative feedbac4 affects the production of hormones in the menstrual cycle. 1igh levels of one hormone may inhibit the production of another hormone.
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1omeostasis is the state reached when each part of the body functions in e5uilibrium with other parts. This is attained through the regulation of the bodily functions by the endocrine and nervous systems.
