Download Parts and functions of the brain (damage also), neuron activity, endocrine system. and more Study notes Psychology in PDF only on Docsity!
Neurons
-The lowest anatomical and functional unit of the nervous system All our thoughts are traces through neurons, these have different tasks, like: o afferent neurons are specialized in relaying messages from the senses to the brain or spinal cord. o Efferent neurons : convey messages from the central to the glands and muscles in order to make movements. o Interneurons : convey info between neurons in the brain and spinal cord. Neuron Structure: o Tail is called the axon , its terminals transmit signals to the dentrites of the neurons, muscles, and other body parts. Some of them are short, some of them are metre long. o The soma, cell body, contains nucleus and carries metabolic functions. Can also receive the signals directly. o Dendrites send messages backward from cell body to their own branches (back propagating), and receive information from other neurons Myelin and Neuron Growth : o Axons are covered in an oily substance called myelin , which increases speed and protects neurons. o As you grow, you create myelin sheaths. This coating has gaps called nodes of ranvier. o This growth allows for more connections through neurons.
NEUROTRANSMITTERS
Between neurons is neurotransmitter chemicals that make connections:
Located in synaptic vesicles. the brain, the spinal cord, the glands and few other parts of the body. There are over 100 chemical substances manufactured by the body. Neurotransmitters can only affect those neurons that contain receptors to receive molecules matching their shape. The interaction between near transmitter and the receptor is not controlled by their drugged influence but their mutual influence. The action of neurotransmitters when they add enter their septra side it's whether excitatory(To fire) or inhibitory (not to fire). the threshold , is when the excitatory influence exceed inhibitory influence. The cell body is always working to manufacture more neurotransmitters, unused neurotransmitter molecules may be broken down to be recycled and used again, lastly the process called reuptake occurs where substance may be taken back into the Axon terminal ready for immediate use. Most of the transmission occurs chemically but electrical transmission occurs in the retina olfactory bulb and the cerebral cortex.
- ACH - acetylcholine for learning. Excitatory or inhibitory effects, excitatory effect on the skeletal muscle fibres, so they contract so that we can move. Inhibitory effect on the muscle fibers in the heart keeping the heart from beating too fast. mono amines: o DA- dopamine for pleasure, fear, learning. Both excitatory and inhibitory effects o NE- neropinephine, related to eating and sleeping.
- Serotonin , mood regulation, aggression, impulsivity. Inhibitory effects. Link to depression anxiety disorders, Deficiency in serotonin and norepinephrine can cause depression. Amino acids :
- Glutamate : primary excitatory transmitter in the brain, its released by 40% of neurons and 's active in the higher brain centres there are involved in learning thought and emotions.
- GABA , thought control. Main inhibitory transmitter in the brain, widely distributed in the central nervous system. Facilitate the control of Anxiety in humans. Abnormality: epilepsy.
- Endorphins - reduce plain, enhance mood. One single neurotransmitter is not responsible for a whole mental function for example memory is modified by a collection of neurotransmitters including acetylcholine, epinephrine, norepinephrine and serotonin. The peripheral nervous system Autonomic nervous system: 1- Sympathetic, prepares u for a threat, real triggers. U need both for full sexual response 2- Parasympathetic, when u relax, slows heart rate, improves digestion, immune response. For stimulating. Somatic nervous system consists of all the sensory nerves which transmit information from the sense receptors to the central nervous system.
The brainstem: It handles functions that are vital to our physical survival. Damage is life threatening. Medulla is the part that controls heartbeat breathing blood pressure coughing and swallowing. The reticular formation please a crucial role in arousal and attention and it screens messages entering the brain, blocks some of them and sends other on to the higher brain centres for processing. It also determines how alert we are. Pons Play the role in movement and exerts an influence on sleeping and dreaming.
Human brain:
Blue= basic surviving structures Forebrain Hindbrain The most essential human part of the human being is the cerebrum and its cortex. The cerebral h. Have a thin outer covering called cerebral cortex. Which is responsible for higher mental processes of language and thinking. The cerebral accord it has three types of area:
- Sensory input areas where vision hearing touch pressure and temperature register.
- Motor areas which controls movement
- Association areas which is a house for memories involved in thoughts perception in language. Corpus callosum: sotto Cerebrum: Composed of two cerebral hemisphere Which are connected at the bottom by a thick band of nerves fibrous call the corpus callosum. This makes possible to transfer information. The right cerebral hemisphere controls movement and feeling in the left side of the body, the left cerebral hemisphere controls the right side of the body. Those hemispheres have a thin outer covering call the cerebral cortex which is responsible for the higher mental processes of language memory and thinking.
Hypothalamus: relay station for sensations, weighs 56 grams, regulate hunger, thirst, sexual behaviour, wide variety of emotions. Regulates internal body temperature a biological clock which is our body rhythms and the timing of our sleep. Performs all body functions except blood pressure, heart rhythm, breathing. Limbic system: feeling emotions, Series of structures including the amygdala and the hippocampus, Which are involved in emotional expression, memory and motivation. Thalamus: Relay all the information that flows in and out of the higher brain centres, information from all the senses except smell. The sensor information travels first to the parts of the thalamus or hypothalamus and then to the area of the cortex that handles vision etc. It also effects our ability to learn information especially if it's a verbal and regulate sleep cycles. Cerebellum: Has two hemispheres, its mean functions are to execute movement and regulate muscle posture, it also coordinates and orchestrates the moment necessary to perform everyday activities, like guiding food from the plate to mouth, walking straight. Damage: difficulties in simple acts. Reticular formation: sopra Spinal cord: sopra Medulla: sopra Pons: relay station for movement
Principal structures in lambic system:
Limbic cortex : sopra Pituitary gland sotto Amygdala : Plays an important role in emotion particularly in response to unpleasant or punishing stimuli. Involved in aspects of learning such as learn fears avoiding dangerous situations. It helps make associations between external events and emotions related to those events. Damage : inability to recognize facial expressions showing fear or anger and voice expressing these emotions. Hippocampus : Located in the interior temporal lobes, it's essential in the formation of conscious memory, if destroyed you wouldn't be able to store or recall any new personal or cognitive information, cell generation occurs in the hippocampus in human adults. Regenerate neurones and damaged neurones can spout new dendrites and re-establish connections with other neurones to assume some of the functions of the brain cell lost, Axons also are able to grow. The brain's ability to reorganize and to compensate for brain damage is called plasticity. Corpus callosum : series of axons which connects the 2 sides of the brain. Cerebral cortex of the left hemisphere: o The left hemisphere handles language functions and understanding the speech and is specialized for mathematical abilities, processes information in an analytical step by step manner. o The right hemisphere special at visual spatial relations, it better at recognizing patterns familiar voices melodies and music and things that are seen. damage to it have difficulty with special orientation even in familiar surroundings. with a condition called unilateral neglect patient read
we saw. damage people lose their ability to identify objects although they are able to identify it by touch or other senses. Cerebellum : sopra Temporal lobe : Involved in the reception and understanding of auditory stimuli and the side where the hearing registers is the primary auditory cortex. Broca’s area : ability to produce language, damage non-fluent aphasia: unable to say specific words. He was one of the first scientists to demonstrate the existence of localized functions in the cerebral cortex, it's involved in directing muscle movement to produce speech sounds.
- It's specialized area for grammar. Prefrontal cortex : personality, decision making, managing emotions. The endocrine system It's a series of ductless glands that manufacture and secrete chemicals known as hormones. hormones are released in one part of the body but also have effect on the other part of the body. Released into the bloodstream and travel throughout the circulatory system. some neurotransmitters act as hormones such as Norepiphrine and vasopressin. The pituitary gland located in the brain, below the hypothalamus and it's controlled by it. Consider to be the master gland because it releases the hormones that activate other glands in the endocrine system. the thyroid gland regulates debate at which food is metabolized, too much thyroxine can result in hyperthyroidism and too little causes hypothyroidism. the adrenal glands located above the kidneys, produce epinephrine and norepinephrine Hormones that activate the sympathetic nervous system, these glands releases corticoids which controls the body's salt balance and release sex hormones. the pancreas regulates the body's blood sugar levels by releasing insulin and Glucagon and also produces digestive enzymes; diabetes is when too little insulin is produced, hypoglycaemia is the opposite. the sex glands are the gonads, they are activated by the pituitary gland And are also responsible for the secondary sex characteristics, androgen is the male sex hormone which influence sexual motivation, in female are estrogen and progesterone which helps regulate the menstrual cycle. males have more androgens and females have more estrogen.
