psych 101 chapter 2 review – Flashcards

Neurons are the elementary components of the nervous system, the body's speedy electrochemical information system. A neuron sends signals through its axons, and recerives signals through its branching dendrites. If the combined signals are strong enough, the neuron fires, transmitting an electrical impulse ( the action potential) down its axon by means of a chemistry-to-electricity process. The neuron's reaction is an all-or-none process.

when action potentials reach the end of an axon (the axon terminals), they stimulate the release of neurotransmitters. These chemical messengers carry a message from the sending neuron across a synapse to receptor sites on a receiving neuron. The sending neuron, in a process called reuptake, then normally reabsorbs the excess neurotransmitter molecules n the synaptic gap. The receiving neuron, if the signals from that neuron and others are strong enough, generates its own action potential and relays the message to other cells.

Each neurotransmitter travels a designated path in the brain and has a particular effect on behavior and emotions. Acetylcholine aggects muscle action, learning, and memory. Endorphins are natural opiates released in response to pain and exercise.

The neurons system is divided into the central nervous system (CNS- the brain and spinal cord) and the peripheral nervous system (PNS), which connects to CNS to the rest of the body by means of nerves. The PNS has two main divisions. The somatic nervous system enables voluntary control of the skeletal muscles. The autonomic nervous system, through its sympathetic and parasympathetic divisions, controls involuntary muscles and glands. Neurons are the basic building blocks of the nervous system. Sensory neurons carry incoming information from sense receptors to the brain and spinal cord, and motor neurons carry information from the brain and spinal cord out to the muscles and glands. Interneurons communicate within the brain and spinal cord and between sensory and motor neurons. Neurons cluster into working neural networks.

The endocrine system is a set of glands that secrete hormones into the bloodstream, where they travel through the body and affect other tissues, including the brain. In an intricate feedback system, the brain's hypothalamus influences the pituitary gland ( the endocrine system's master gland) which influences other glands (such as the adrenals) to release hormones, which in turn influence the brain.

Clinical observations and lesioning have revealed the general effects of brain damage. MRI scans now reveal brain structures, and EEG, PET, and fMRI (functional MRI) recordings reveal brain activity.

the brainstem, the oldest part of the brain, is responsible for automatic survival functions. its components are he medulla (which controls hearbeat and breathing). the pons (which helps coordinate movements), and the reticular formation (which affects arousal). The thalamus, the brain's sensory switchboard, sits above the brainstem. The cerebellum, attached to the rear of the brainstem, enables some types of nonverbal learning and memory; coordinates muscle movement; and helps process sensory information. The limbic system's neural centers include the hippocampus (which processes memories of facts and episodes), the amygdala (involved in emotions such as agression and fear), and the hypothalamus(involved in various drives, maintenance functions, and pleasurable rewards). The hypothalamus also controls the pituitary, which influences other glands to release hormones.

the cerebral cortex is the thin layer of interconnected neurons covering the brain's hemispheres. Prominent folds divide each hemisphere into four lobes-the frontal, parietal, occipital, and temporal.

some brain regions serve specific functions. The motor cortex (at the rear of the frontal lobes) controls muscle movement. The sensory cortex (at the front of the parietal lobes) receives information from our senses. Most of the cortex is devoted to uncommitted association areas, which integrate information involved in learning, remembering, thinking, and other higher level functions. Language depends on a chain of events in several brain regions, particularly Broca's area, Wernicke's area, and the angular gyrus. Damage to any of these regions may cause one of several types of aphasia.

If one hemisphere is damaged early in life, the other will pick up many of its functions. This plasticity diminishes later in life. Some brain areas are capable of neurogenesis(forming new neurons)

Split-brain research (experiments on people with a severed corpuscallosum) has confirmed that in most people, the left hemisphere is the more verbal, and that the right hemisphere excels in visual perception and making inferences. Studies of healthy people with intact brains confirm that each hemisphere makes unique contributions to the integrated functioning of the brain.