Total production of CSF is about ).
Association Areas
Areas in the cerebral cortex that are not involved in primary motor and sensory functions; rather they are involved in higher mental functions such as learning, remembering, thinking and speaking.
Association areas in the Frontal Lobes are concerned with judging and planning;
Damage may lead to intact memory but inability to plan out something.
Personality may also be affected.
Association areas of other lobes are related to other mental functions; i.e. Temporal Lobe enables us to recognize faces; damage to this area causes inability to identify people (although facial features can be described), and gender and approximate age too.
Association areas in the posterior lobes are involved in perception and memory. Damage leads to difficulty in perceiving speech.
Spinal Cord
Continuation of the Medulla Oblongata.
The spinal cord is about 45 cm long in men and 43 cm long in women and weighs about 35-40 grams.
The vertebral column (back bone), encapsulating the spinal cord, is about 70 cm long comprising vertebra in the vertebral column.
The spinal cord is much shorter than the vertebral column.
Signals arising in the motor areas of the brain travel back down the cord and leave in the motor neurons.
The spinal cord also acts as a minor coordinating center responsible for some simple reflexes like the withdrawal reflex.
Reflex - rapid (and unconscious) response to changes in the internal or external environment, needed to maintain homeostasis
Reflex arc: the neural pathway over which impulses travel during a reflex. The components of a reflex arc include:
Receptor - responds to the stimulus
Afferent pathway -- sensory neuron
Central Nervous System
Consists of the spinal and cranial nerves; these connect the CNS to the rest of the body. PNS connects the body’s sensory receptors to the CNS, and the CNS to the muscles and glands.
The part of the nervous system that includes all parts of the nervous system except the brain and the spinal cord Includes:
Somatic Division / Somatic Nervous System/ SNS
Autonomic division / Autonomic Nervous System/ ANS
PNS has two important parts
Skeletal/Somatic Nervous System
Controls the voluntary movements of our skeletal muscles.
It reports the current state of skeletal muscles and carries instructions back.
Controls the voluntary movements of the skeletal muscles.
Controls the involuntary movements all over the body; movements of the heart, lungs, stomach, glands and other organs.
Autonomic Nervous System (ANS)
Considered as the “self-governing or self-regulatory mechanism” because of its involuntary operation.
Controls the glands and muscles of internal organs e.g. heart, stomach, and glandular activity.
A.N.S. has a dual function; i.e. both arousing and calming.
Comprises two sub systems; Sympathetic and parasympathetic nervous systems.
This part of ANS arouses us for defensive action fight or flight.
If something alarms, endangers, excites, or enrages a person, the sympathetic nervous system accelerates heartbeat, slows digestion, raises the sugar level in blood, dilates the arteries and cools the body through perspiration; makes one alert and ready for action.
When the stressful situation subsides, parasympathetic nervous system begins its activity.
It produces an effect opposite to that of sympathetic nervous system.
It conserves energy by decreasing heartbeat, lowering blood pressure, lowering blood sugar and so on.
In daily life situations, both sympathetic and parasympathetic systems work together to keep us in steady internal state maintaining the homeostasis.
Studying the Structure and Function of the Brain
Electroencephalogram (EEG): recording of the electrical signals being transmitted within the brain, through electrodes attached to the skull.
Computerized Axial Tomography (CAT): a computer constructs an image of the brain by combining thousands of separate X-rays taken from slightly different angles.
Magnetic Resonance Imaging (MRI): the scan produces a powerful magnetic field to provide a computer generated, detailed image of the structure of the brain.
Super Conducting Quantum Interference Device (SQUID): a scan sensitive to minute changes in the magnetic field occurring when neurons are firing.
Positron Emission Tomography (PET): a scan showing biochemical activity within the brain at any given moment.
Endocrine system is a collection of glands that produce hormones that regulate body's growth, metabolism, and sexual development and function.
The hormones are released into the bloodstream and transported to tissues and organs throughout the body.
Although there are eight major endocrine glands scattered throughout the body, they are still considered to be one system because they have similar functions, similar mechanisms of influence, and many important interrelationships.
Endocrine glands are known as the “Managers of Human Body”.
Endocrine system is the system in which a number of glands secrets numerous hormones directly into the blood stream which regulate:
Body’s growth
Metabolism
Sexual development and functions, and
Other vital functions of the body
Endocrine glands are ductless glands that secrete their hormones directly into the bloodstream.
Hormones act as chemical messenger controlling various functions, reaching to the tissues and other vital organs of the body.
The pineal gland, also known as pineal body, is found in the brain stem.
It is small and cone-shaped in structure
Affects reproductive development
Daily physiologic/ biological cycles
Size and shape
It is a small gland__ diameter of about 1 centimeter or size of a pea.
Location
It is connected with the hypothalamus by a slender stalk and also surrounded by bone.
Secretes a number of different hormones that influence/affect various other endocrine glands.
There are two distinguishable regions in the gland that have different secretions and functions:
a. The anterior lobe
Growth Hormone: Protein that regulates and also stimulates the:
Growth of bones,
Muscles, and other organs of the body by promoting protein synthesis.
The effect of this hormone is important and very much apparent because it affects height.
Growth Hormonal Problems
Dwarfism
f there is very little or no secretion of this hormone in a child, then the child may become a pituitary dwarf__ small in stature.
Gigantism
If there is too much secretion of this hormone in the body, then there is exaggerated bone growth in a person and the person become exceptionally tall or a giant.
This rare condition is usually caused by a pituitary tumor and can be treated by removing the tumor.
When the pituitary gland fails to produce adequate amounts of growth hormone, a child's growth in height is impaired/ disturbed.
Hypoglycemia (low blood sugar) may also occur in children who have deficiency of this growth hormone __ affects particularly infants and young children with this condition.
Thyroid-stimulating hormone: Affects the glandular cells of the thyroid so that it secretes thyroid hormone. The thyroid gland become enlarged and secretes too much thyroid hormone if there is hyper secretion of thyroid- stimulating hormone.
Adrenocorticotropic hormone: Cortical hormones especially cortisol are secreted when it reacts with the receptor cells in the cortex of the adrenal gland.
Gonadotropic hormones: Regulate the development, growth, and function of gonads and ovaries by reacting along with receptor cells present in these organs.
Prolactin Hormone: Helps in promoting the development of glandular tissues in the female breasts during pregnancy and as a result stimulates milk production after the birth of the infant.
b. Hormones of the Posterior Lobe
These hormones are:
i. Antidiuretic hormone
Helps in the reabsorption of water by the kidney tubules__ as a result of which less amount of water is lost from the body as urine.
This system/ mechanism conserve water for the body.
ii. Oxytocin
Helps in the contraction of smooth muscles in the walls of the uterus.
It also stimulates the ejection of milk from the lactating breast.
3. Hypothalamus
Part of the central nervous system that is involved in controlling and activating involuntary functions of the body such as,
Hormonal system
Other body functions as well__ regulating sleep and stimulating appetite