Brain Anatomy & Physiology Overview

A gland in the brain that releases hormones that regulate other glands. These hormones are called tropic hormones.

The hypothalamus, a part of the brain, controls the anterior pituitary gland by releasing regulatory factors called hormones. These hormones help regulate the release of hormones from the anterior pituitary.

The pineal gland, part of the epithalamus, produces melatonin, a hormone that induces sleepiness and acts as an antioxidant.

The limbic system is responsible for emotions, drives, learning and memory. It can be modified by the cerebral cortex, alcohol, and drugs.

The cerebrum is the conscious brain, responsible for thinking, learning, and complex behaviors. It consists of five lobes: frontal, parietal, temporal, occipital, and insula.

A vital brain region controlling many bodily functions including visceral activity, hormone production, temperature regulation, basic drives, and sleep-wake cycles.

The hypothalamus acts as a control center for all internal organ activities, ensuring smooth operation of the digestive, respiratory, and circulatory systems.

The hypothalamus synthesizes hormones like ADH and oxytocin, regulating fluid balance and social bonding respectively.

The hypothalamus acts like a thermostat, maintaining optimal body temperature through sweating or shivering.

The hypothalamus drives essential behaviors like hunger, thirst, and sexual motivation, ensuring survival and reproduction.

The hypothalamus orchestrates our daily sleep-wake rhythm, adjusting hormone levels and promoting either alertness or sleepiness.

The hypothalamus is integrated into the limbic system, a network of brain structures involved in emotions, motivation, and memory.

The hypothalamus participates in the Reticular Activating System, a network responsible for alertness and arousal.

The outermost layer of the brain, responsible for higher-level functions like consciousness, thought, and language.

The concept that specific areas of the cerebral cortex are dedicated to processing information from particular parts of the body or sensory systems.

The representation of the body's surface in the brain, where specific areas of the cortex correspond to specific parts of the body.

The area in the parietal lobe responsible for receiving sensory information about touch, temperature, pressure, and pain from the body.

A distorted representation of the human body, based on the relative amount of brain tissue devoted to specific body parts in the somatosensory cortex.

The specialization of functions in each cerebral hemisphere, where one hemisphere may be dominant for certain tasks.

The relationship between the brain and the body where the left side of the brain controls the right side of the body, and vice versa.

Numerically labeled regions of the cerebral cortex that correspond to different functional areas of the brain.

The part of the brain that commands voluntary movement of skeletal muscles. It's located in the precentral gyrus of the frontal lobe.

A region in the frontal lobe (usually the left side) responsible for motor speech. It helps you form words and sentences.

A map of the human body in the brain, showing how much area in the somatosensory cortex is devoted to different body parts. The more sensitive the area, the larger its representation.

The left hemisphere of the brain controls the right side of the body, and the right hemisphere controls the left side.

These brain areas take sensory information and integrate it with past experiences and knowledge, helping you interpret what you are sensing.

The left hemisphere is primarily responsible for logical and sequential processing, including language, math, and analytical thinking.

The right hemisphere specializes in spatial abilities, music, art, and facial recognition. It also plays a role in understanding emotions.

A thick band of nerve fibers that connects the two hemispheres of the brain, allowing them to communicate with each other.

The prefrontal cortex is responsible for higher-level cognitive functions like learning, judgment, planning, generating ideas, personality development, empathy, conscience, and regulating mood. It's strongly connected to the limbic system.

The premotor cortex is like a memory bank for skilled movements, such as playing an instrument or typing. It helps plan and control movements, receiving sensory input to guide actions.

The GIA integrates sensory information from various parts of the brain, creating a unified meaning and allowing us to understand the world around us. It includes Wernicke's area, which interprets language.

Association areas receive information from other areas of the brain and process it to create a comprehensive understanding. They play a crucial role in interpreting sensory data and integrating it with other information.

Sensory information starts at the primary sensory cortex (e.g., somatosensory, visual, auditory). It's then interpreted in the corresponding association area, like the somatosensory association area. Finally, the information is sent to the prefrontal cortex for planning and decision-making.

The primary motor cortex sends out signals to skeletal muscles and the spinal cord, initiating and controlling voluntary movements.

The cerebellum receives sensory information from proprioceptors (position sense) and receives movement intent from the cortex. It then helps correct ongoing movements to ensure smooth and coordinated actions.

The prefrontal cortex is closely connected to the limbic system, which is responsible for emotions and drives. This link allows us to control our emotional responses and make informed decisions.

Dermatomes are areas of skin innervated by a single spinal nerve root. They follow a segmental pattern because they are derived from cells of a somite, which develops into the skin.

The Peripheral Nervous System (PNS) is divided into two main branches: the Afferent Division, which carries sensory information to the CNS, and the Efferent Division, which carries motor information from the CNS to effectors.

The Somatic NS controls voluntary movements of skeletal muscles, while the Autonomic NS controls involuntary actions of smooth muscle, cardiac muscle, and glands.

The Somatic NS carries signals from the brain to skeletal muscles via two motor neurons, enabling you to move your body consciously.

Ascending tracts in the spinal cord carry sensory information from the body to the brain, while descending tracts carry motor commands from the brain to the body.

The PNS is the network of nerves that connects the central nervous system (CNS) to the rest of the body. It carries sensory information to the CNS and motor commands from the CNS to muscles and glands.

Nerves are bundles of axons (nerve fibers) that travel together in the PNS. They connect receptors (sensory organs) and effectors (muscles and glands) to the CNS.

Axons are grouped into bundles called fascicles. These fascicles are further wrapped in membranes: epineurium (around fascicles), perineurium (around a fascicle), and endoneurium (around axons).

A plexus is a network where nerves branch and rejoin, creating alternative paths for information. This ensures function even if one path is damaged.

The Brachial Plexus is a network of nerves responsible for controlling the muscles and sensory information of the arm and hand.

A dermatome is a specific area of skin that is supplied by a single spinal nerve.

The Phrenic Nerve controls the diaphragm, a muscle essential for breathing. It originates from cervical nerves (C3-C5).

The Femoral Nerve controls the muscles of the thigh and provides sensation to the front of the thigh, knee, and lower leg. It originates from lumbar nerves (L2-L4).

The Dorsal Columns are a sensory pathway in the spinal cord responsible for transmitting fine touch and pressure sensations from the body to the brain.

The Spinothalamic tract is a sensory pathway in the spinal cord that carries pain signals from the body to the brain.

Sensory neurons carrying touch and pressure information synapse in the medulla, where they also cross over to the opposite side of the brain.

The primary somatosensory cortex is the part of the brain responsible for receiving and processing sensory information from the body, including touch, pressure, temperature, and pain.

The corticospinal tract is the main pathway for voluntary motor control, carrying signals from the brain to the spinal cord and muscles.

Motor neurons in the corticospinal tract cross over in the medulla, so the left side of the brain controls the right side of the body and vice versa.

The ventral horn of the spinal cord is where motor neurons synapse with other neurons, before sending signals to the muscles.

Brain function depends on connections between different functional areas, allowing sensory information to be processed, interpreted, and acted upon.

The part of the autonomic nervous system responsible for 'rest and digest' functions, conserving energy and promoting maintenance and repair.

The parasympathetic nervous system uses a long preganglionic fiber that releases acetylcholine onto a short postganglionic fiber, also releasing acetylcholine at the target organ.

The parasympathetic nervous system constricts the pupils, making them smaller.

The parasympathetic nervous system slows down the heart rate.

The parasympathetic nervous system constricts the bronchioles, narrowing the airways.

The parasympathetic nervous system contracts the urinary bladder, promoting urination.

The parasympathetic nervous system stimulates digestion, absorption, and excretion, increasing peristalsis, salivation, and bile secretion.

The Vagus nerve is the main nerve responsible for parasympathetic functions, innervating many vital organs.

The sympathetic nervous system is activated during stress, causing a 'fight-or-flight' response. It prepares the body for immediate action by increasing heart rate, blood pressure, and respiration, mobilizing energy reserves, and redirecting blood flow to muscles and brain.

The sympathetic nervous system triggers several physiological changes during stress, including increased heart rate and breathing, dilation of pupils, sweating, release of glucose, and rerouting blood flow. These responses prepare the body for immediate action.

The chain of sympathetic ganglia along the spinal cord has three pathways for transmitting signals: direct synapses, ascending or descending synapses, and peripheral synapses.

During stress, the adrenal medulla releases epinephrine (adrenaline) into the bloodstream, further increasing heart rate, blood pressure, and energy mobilization. In chronic stress, the adrenal cortex releases cortisol, a hormone involved in long-term stress response.

Muscarinic receptors are a type of neurotransmitter receptor that are activated by acetylcholine. They're found in the parasympathetic nervous system (PSNS), which controls 'rest and digest' functions, and some sympathetic nervous system (SNS) targets.

The M1 receptor boosts gland secretion (like saliva), increases gut activity, and plays a part in the central nervous system (CNS).

The M2 receptor slows down your heart rate and contractile force, as well as constricting bronchioles (airways).

The M3 receptor triggers smooth muscle contraction, impacting the GI tract, eyes, bladder, and blood vessels.

Adrenergic receptors are activated by adrenaline and noradrenaline. These receptors influence the sympathetic nervous system (SNS) which is responsible for 'fight or flight' responses.

The Alpha 1 receptor causes the release of calcium within cells, ultimately leading to constriction of blood vessels, especially to the skin and gut. It also constricts sphincters in the digestive and urinary systems.

The Alpha 2 receptor inhibits the production of cAMP (cyclic AMP), which reduces insulin release.

The Beta 1 receptor boosts heart rate and force (positive inotropism and chronotropism), increases renin secretion in the kidneys (more blood volume), and increases metabolic rate (burns more energy) in the liver, muscles, and fat.