Final exam 2085 Review

Cell function
Note: understanding these concepts will help you later to understand how action potentials are created.

What is a sodium-potassium exchange pump?

= Moves sodium and potassium ions against large concentration gradients. It moves two potassium ions into the cell where potassium levels are high, and pumps three sodium ions out of the cell and into the extracellular fluid.

What is a threshold stimulus?

= Is the smallest amount of stimulation or force that is needed to initiate a response. 

What is an action potential?

=Is a sequence of changes that spreads and decreases and reverses the resting membrane potential and then restores it to its resting state.

Integumentary system

What are tactile discs? = An inviting tactile material that challenges children's sense of touch on both hands and feet. At the same time, it develops the ability to describe sense impressions verbally.

What are tactile corpuscles? = Small structures located in the skin that are responsible for detecting light touch. They are found in the dermal papillae of the skin.

What is Meissner corpuscle? = Touch-sensitive nerve endings found in the skin, particularly in sensitive areas like fingertips and lips. They detect light touch and texture changes, aiding in tactile perception and fine motor control.

What is the function of Ruffini corpuscles? = They are slowly adapting mechanoreceptors which respond to stretch and movement and do not transmit discriminative touch stimuli.  

Muscles
Note: there are videos about the events that occur during muscle contraction that are very helpful to visualize what is happening. Knowing the muscles of the body that you learn in lab can help you understand better the information.

What are the functions and characteristics of smooth muscle?

= Moves substances in the digestive, urinary, and reproductive tracts. Controls diameter of respiratory passageways and blood vessels. Characteristics:

Its cells are long, spindle shaped, without striations, and with a single central nucleus. Also, cells have

different organization of actin and myosin and different functional characteristics. Cells have no T tubules, myofibrils, or sarcomeres. They have scattered myosin fibers with more heads per thick filaments. The thin filaments are attached to dense bodies which transmit contraction from cell to cell.

What are the functions and characteristics of cardiac muscle? = Characteristics: cells or cardiocytes are small, short, branched, striated, most have a single nucleus, and they are interconnected by intercalated discs. They have short, wide T tubules and no triads. Their sarcoplasmic reticulum has no terminal cisternae. The cells use aerobic metabolism and have many mitochondria as well as a high content of myoglobin, a protein that stores oxygen. It is found only in the heart forming the walls of the heart and pumping blood through the blood vessels. Functions: 1. Keep circulating blood moving. 2. Maintains blood (hydrostatic) pressure.

What are the functions and characteristics of skeletal muscle? = Characteristics: Its cells are very long, cylindrical, striated, and multinucleated. It is associated with the skeleton in skeletal muscles where it combines with connective tissue, blood vessels, and nervous tissue. It is the most abundant type of tissue in the human body. Functions: Produces skeletal movement of body parts, maintains posture by stabilization of the position of the skeleton, Guards the entrances and exits to the digestive and urinary tracts (anal sphincter and external urethral sphincter), Generates heat and thus helps with maintenance of body temperature, Supports and protects soft tissues and internal organs and stores nutrients reserves.

What is the structure of a skeletal muscle? Hint: know the order of the structures. = Epimysium: The outermost layer of tissue surrounding the entire muscle. Perimysium: The middle layer surrounding bundles of muscle fibers. Endomysium: The innermost layer surrounding individual muscle fibers.

What are the events that occur during muscle contraction? Hint: learn the order of events in order. = 1. ACh released: ACh is released at the neuromuscular junction and binds to ACh receptors on the sarcolemma. 2. Action potential reaches T tubule: An action potential is generated and spreads across the membrane surface of the muscle fiber and along the T tubules. 3. Sarcoplasmic reticulum releases Ca+: The sarcoplasmic reticulum releases stored calcium ions. 4. Active sites exposed and cross-bridges form: Calcium ions bind to troponin, exposing the active sites on the thin filaments. Cross-bridges form when myosin heads bind to those active sites. 5. Contraction cycle begins: The contraction cycle begins as repeated cycles of cross-bridge binding, pivoting, and detachment occur-all powered by ATP. 6. ACh is broken down: ACh is broken down by acetylcholinesterase (AChE), ending action potential generation. 7. Sarcoplasmic reticulum reabsorbs Ca+: As the calcium ions are reabsorbed, their concentration in the cytosol decreases. 8. Active sites covered, and cross-bridge formation ends: Without calcium ions, the tropomyosin returns to its normal position and the active sites are covered again. 9. Contraction ends: Without cross-bridge formation, contraction ends. 10. Muscle relaxation occurs: The muscle returns passively to its resting length.

What can lead to increase oxygen consumption?

= Physical activity and exercise, Fever or elevated body temperature, Stress, both physical and emotional, Illness or infection, Cold temperatures or high altitudes & Hyperthyroidism or certain medications.

What is rigor mortis?

= it is a fixed muscular contraction after death. It is caused when ions pumps cease to function; ATP is depleted, and calcium builds up in the cytosol.

What muscles are near the sacral region?

= The anterior surface: Piriformis, Coccygeus, Iliacus.

The posterior surface: Gluteus maximus, Multifidus lumborum & erector spinae.

What muscles are near the cervical region? What nerve innervates the diaphragm?

= Sternocleidomastoid (SCM), Scalene Muscles (Anterior, Middle, and Posterior), Trapezius, Levator Scapulae, Longus Colli & Longus Capitis.

What nerve innervates the diaphragm?

= The phrenic nerve innervates the diaphragm.

How do resting muscles generate most of its ATP?

=Most of the ATP required for resting or moderately active muscles is provided by aerobic respiration.

Respiration and ATP
Note: remember cellular respiration is a metabolic pathway that breaks down glucose and produces ATP.

What is aerobic respiration?

= The primary source of energy for cardiac and smooth muscle tissue.

What is anaerobic respiration?

= The type of respiration through which cells can break down sugars to generate energy in the absence of oxygen.

What happens during intense exercise with aerobic respiration? Hint: has to do with oxygen availability.

= The breathing rate and volume of each breath increases to bring more oxygen into the body and remove the carbon dioxide produced.

What happens during activities that require aerobic endurance?

= During aerobic exercise, your heart pumps oxygenated blood to working muscles to help them burn fat and carbohydrate for fuel, which in turn enables you to perform for extended periods.

What happens during anaerobic glycolysis?

=Anaerobic glycolysis involves the breakdown of glucose to pyruvic acid (pyruvate) and, subsequently, to lactic acid (lactate).

Nervous system
Note: remembering how the nervous system is divided will provide you a better understanding of the information.

What are the functions of the nervous system?

= It guides everyday activities such as waking up; automatic activities such as breathing; and complex processes such as thinking, reading, remembering, and feeling emotions.

What are spinal nerves?

=Spinal nerves send electrical signals between your brain, spinal cord and the rest of your body.

What composes the central nervous system?

= Central Nervous System (CNS): Brain and spinal cord.

What composes the peripheral nervous system?

=Peripheral Nervous System (PNS): Composed of nerves and ganglia outside of the brain and spinal cord.

What is perineurium?

=Perineurium: A protective connective tissue layer surrounding nerve fascicles in the peripheral nervous system.

What is the efferent division of the peripheral nervous system? hint: has to do with voluntary movement.

= Carries motor commands from CNS to PNS muscles and glands.

What is the somatic nervous system?

=Controls voluntary and involuntary (reflexes) skeletal muscle contractions.

What is the function of the afferent system?

= To transmit sensory information from sensory receptors (such as in the skin, muscles, joints, and organs) to the central nervous system (CNS).

What is the location of the ulnar nerve?

= It starts at the brachial plexus in the armpit and: Connects to the C8 cervical vertebra and the T1 thoracic vertebra (the middle of the brachial plexus). Runs down the front of the upper arm near the axillary and brachial arteries.

What is filum terminale?

= Is the nonfunctional continuation of the end of the spinal cord. It usually consists of fibrous tissue without functional nervous tissue.

What is the white matter of the spinal cord composed of?

= Is composed of dense tracts of neuronal axons that are heavily myelinated by glial cells known as oligodendrocytes.

What is the function of the dorsal ramus?

= To carry nerve axons for deep muscles and skin of posterior surface of the trunk.

What is the specific location of somatic motor nuclei?

= In the upper part of the midbrain at the level of the superior colliculus.

What does the dorsal root ganglia mainly contain?

= Mainly contain Synapses.

Neuroglia Note: glial cells.

What are the functions of neuroglia?

= They provide homeostatic support, protection, and defense to the nervous tissue.

What type of glial cells are found in the peripheral nervous system?

= In the PNS, the main glial cells are Schwann cells, satellite cells, and enteric glia.

What type of glial cells are found in the central nervous system?

= Oligodendrocytes, astrocytes, ependymal cells and microglia.

What are the functions of astrocytes?

= Functions include creating a framework and structural support for the neurons, maintaining the blood-brain barrier, regulating and controlling the interstitial environment, guiding neuron development.

What are the functions of Schwann cells?

= Schwann cells (neurilemma) from myelin sheath around axons in the peripheral nervous system.

Each Schwann cell forms a myelin coat around a single axon (different than the oligodendrocytes). One schwann cell sheaths one segment of axon and many schwann cells sheath the entire axon.

What glial cell surrounds neurons in ganglia?

= Satellite cells

Neurons
Note: a neuron (also known as nerve cell) is an electrically excitable cell that takes up, processes and transmits information through electrical and chemical signals. Knowing the structure of a neuron can help you understand better the information.

What is the structural classification for neurons?

= Multipolar, bipolar, and unipolar neurons.

What is a postsynaptic neuron?

= Is a nerve cell that receives neurotransmitter signals from a presynaptic neuron at a synapse, enabling communication between neurons in the nervous system.

What is a presynaptic neuron?

= Releases a chemical messenger called a neurotransmitter which diffuses through the fluid in the synaptic cleft and binds to receptors in the plasma membrane of the postsynaptic neuron.

What are the steps involved in transmission at a cholinergic synapse? Hint: know the order of events in order.

= An action potential reaches the axon terminal (synaptic knob) and triggers the opening of voltage-gated calcium channels.

2- Entrance of calcium ions into the synaptic knob causes some synaptic vesicles to fuse with the cell membrane and release (by exocytosis) neurotransmitter into the synaptic cleft.

3- Acetylcholine diffuses across the cleft and binds to receptor sites. This opens sodium channels and causes the post-synaptic membrane to depolarize.

4- Cholinesterase quickly breaks down acetylcholine into acetate and choline. Choline is reabsorbed into the synaptic knobs.

How do neurons generate action potentials?

= Depends on whether a stimulus can depolarize the membrane to the threshold ion balance, preparing neuron for next action potential.

What are the steps in the generation of an action potential? Hint: know the order of events in order.

= Depolarization to threshold

2- Activation of Na+ channels

3- Inactivation of Na+ channels and activation of K+ channels

4- Return to normal permeability and membrane resting potential.

What do the opening of sodium channels in the axon membrane causes?

= Opening of the sodium channels in the axon membrane causes depolarization. The membrane suddenly becomes permeable to sodium ions.

What happens during repolarization of a neuron?

= During the repolarization phase, potassium voltage gated channels allow potassium to go out of the cell.

Preganglionic neurons
Note: preganglionic neurons are in the brainstem or spinal cord of the CNS.

Where are preganglionic neurons of the sympathetic nervous system located?

= The spinal cord.

Where are preganglionic neurons of the autonomic nervous system located?

=Located in the visceral efferent (lateral gray) column of the spinal cord.

What are ganglionic neurons?

= They are part of the autonomic nervous system located in ganglia outside the central nervous system. They receive signals from preganglionic neurons and relay information to target organs like muscles and glands, regulating involuntary functions such as heart rate and digestion in the body.

Where do preganglionic fibers synapse when they leave the CNS?

= Inside the sympathetic ganglia

What are the characteristics of sympathetic preganglionic neurons? Hint: physical characteristics.

= They are short, myelinated, and extend from the thoracic and superior lumbar segments of the spinal cord and enter the anterior roots. Preganglionic neurons cell bodies are in the lateral horns of the spinal cord between segments T1 and L2.

Sympathetic and Parasympathetic nervous system
Note: remember that the parasympathetic nervous system, together with the
sympathetic nervous system, constitutes the autonomic nervous system. Know the difference between: Rest and digest/ fight or flight.

What are the functions of the parasympathetic nervous system?

= Is responsible for the body's rest and digestion response when the body is relaxed, resting, or feeding. It basically undoes the work of sympathetic division after a stressful situation. Also decreases respiration and heart rate and increases digestion.

What are the functions of the sympathetic nervous system?

= Dilate blood vessels, increase blood pressure, contract muscles, secrete sweat from sweat glands, dilate bronchi for more oxygen exchange and contraction of heart.

What is dual innervation?

= Is the instruction that an organ receives from both sympathetic and parasympathetic systems.

What is the thoracolumbar division?

= Is the sympathetic part of the autonomic division because sympathetic neurons originate in the intermediolateral cell column of the lateral horn of the spinal cord at thoracic and upper lumbar spinal cord levels.

What relationship does the autonomic nervous system has with the contraction of the pupil?

= Controls the contraction of the pupil through the action of its sympathetic and parasympathetic divisions.

Senses

What are the general senses?

= Pain, temperature, touch, pressure, vibration, and proprioception.

What are proprioceptors?

= They monitor position of joints and skeletal muscles which is a somatic sensation. Proprioceptors in muscles are called muscle spindles.

What are chemoreceptors?

=They respond to water and lipid soluble substances that are dissolved in the body fluids. They are used to monitor the pH, carbon dioxide, and oxygen levels in arterial blood.

What are baroreceptors?

= Respond to changes in pressure in distensible organs such as the blood vessels and in the digestive, respiratory, urinary tracts.

What are the characteristics of thermoreceptors?

= Temperature receptors are also free nerve endings located in the dermis, skeletal muscles, liver,

and hypothalamus. There is no observable difference between heat and cold receptors.

The sensations of pain and temperature are conducted along the same pathways. They are sent to the reticular formation, thalamus, and to the primary somatosensory cortex.

What are some examples of sensory stimuli?

= Visual: Light entering the eyes.

Auditory: Sound waves reaching the ears.

Olfactory: Chemicals in the air detected by the nose.

Gustatory: Chemicals in food and drink sensed by the tongue.

Tactile: Pressure, vibration, temperature, and pain felt by the skin.

What can cause sensory input to be blocked? Hint: it has to do with sensory neurons in your spinal cord. = Sensory input can be blocked or impaired by physical barriers, damage to sensory organs or nerves, neurological disorders, chemical interference, psychological factors like stress, age-related changes, and extreme environmental conditions.

What are muscarinic receptors?

= These are found at the neuromuscular and neuroglandular junctions of the parasympathetic nervous system. The few cholinergic junctions in the sympathetic system also have them. These cause an indirect response via the activation of enzymes. They are G-coupled receptors. Effects are longer lasting than nicotinic receptors.

How do nicotinic receptors work?

= These receptors are found in the somatic motor system at the neuromuscular junction and on ganglion cells in both the sympathetic and parasympathetic divisions. When Ach attaches to these receptors, chemically gated sodium channels open, depolarizing the membrane, so exposure to Ach on these receptors causes excitation of ganglionic neurons or muscle fiber.

What is the olfactory bulb?

= Is a structure in the brain that processes information about smells detected by the nose, sending signals to higher brain areas for perception and memory. It's crucial for our sense of smell and emotional responses to odors.

How are taste receptors distributed?

= Taste receptors are distributed primarily on the tongue, particularly on its surface and around taste buds located within papillae. They are also found in the roof of the mouth and the throat, playing a key role in detecting different tastes like sweet, salty, sour, bitter, and umami.

Eye
Note: knowing the major structures of the eye will help you understand better the information (what you learn in lab).

What is the function of the iris?

= The iris of the eye is responsible for eye color. Is to control the size of the pupil and hence the amount of light entering the eye.

How does the human lens focus light?

= It focuses light by changing its shape through a process called accommodation. This adjustment allows the lens to bend incoming light rays, ensuring they converge accurately onto the retina for clear vision at different distances.

What are the functions of tears?

= They collect in the lacrimal lake at the medial angle of the eye, pass through the lacrimal puncta (pores), lacrimal canaliculi (canals), lacrimal sac, and nasolacrimal duct where they reach the nasal cavity.

What is the function of the vascular tunic of the eye?

= Provides blood supply to the eye structures, regulates light by absorbing excess light, helps maintain eye temperature, and secretes aqueous humor to maintain intraocular pressure and nourish the eye.

What produces aqueous humor in the eye?

= The ciliary body makes aqueous humor.

What are some characteristics of the fibrous tunic of the eye?

= Provides structural support and protection, consists of the cornea and sclera, The cornea allows light to enter the eye and helps focus it, the sclera is the white, opaque outer layer that maintains the shape of the eyeball.

What are the functions of the ciliary body?

=The ciliary body attaches to the iris and extends to the level of the ora serrata which is the serrated anterior edge of the neural layer of the retina. It contains ciliary processes and the ciliary muscle that attaches the suspensory ligament to the lens. This muscle changes the curvature of the lens. The ciliary processes contain capillaries that secrete aqueous humor.

Ear
Note: knowing the major structures of the ear will help you understand better the information (what you learn in lab).

What is the function of the tympanic membrane?

= Is a thin, semitransparent sheet at the end of the auditory canal that separates the

external ear from the middle ear.

What is the function of the inner ear? Hint: has to do with the organ of Corti.

= Convert sound into electrochemical nerve impulses.

What is the function of the saccule and utricle?

= Responsible for the sensations of position (up, down, etc.) and for the sensation of linear movement (linear acceleration) which together are the sense of static equilibrium.

What is the function of the endolymph in the semicircular canals?

= Rotational movement of the head causes the endolymph inside the semicircular canal(s) to push against the cupula.

What is the function of Otoliths?

= Ear stones/carbonate calcium crystals that add weight to the mass and tug on the hair cells in response to gravity or linear acceleration.

What is the function of the outer ear?

= Collects and channels sound waves down the external acoustic meatus or auditory canal toward the tympanic membrane.

What is the function of the inner ear?

= The inner ear provides the senses of equilibrium and hearing.

What is the function of the auditory tube?

= Connects the middle ear and pharynx. It equalizes air pressure in the middle ear to outside. It also drains the mucus of the middle ear.

Brain
Note: you should know the different structures of the brain and general function. As well as the gross anatomy of the brain.

What protects the brain?

= The brain is protected and supported by the bones of the cranium, the cranial meninges and the cerebrospinal fluid.

What are the meninges?

= The brain is surrounded by three layers of meninges or membranes: 1- the dura mater, 2- the arachnoid, and 3- the pia mater that are continuous with the spinal meninges. They protect the brain from cranial trauma.

What is CSF?

= The Cerebrospinal fluid or CSF is formed by the cells of the choroid plexus and surround all the exposed surfaces of the CNS. It interchanges with the interstitial fluid of the brain.

What is subarachnoid space?

= It is space between the arachnoid and pia mater. It contains cerebrospinal fluid or CSF.

What is the function of the Thalamus?

= Is a sensory relay center for all types of sensory information except olfactory.

What does the medulla oblongata regulate?

= Regulate autonomic functions (heart rate and blood flow and pressure) and respiratory centers (respiratory rate and rhythm).

What are some characteristics of the CSF?

= Cushions delicate neural structures, supports the brain, and transport nutrients, chemical messengers, and waste products throughout the central nervous system.

What is the function of the hypothalamus?

= Provides subconscious control of skeletal muscle, controls autonomic function.

What is the function of the cerebral aqueduct?

= Its function is to allow cerebrospinal fluid flow between these ventricles.

What are the sensory areas in the cerebrum? Hint: learn the function of each. Example: occipital lobe has to do with vision.

= The primary visual cortex found in the occipital lobe

receives information from sight receptors.

2- The auditory found in the temporal lobe receives information from sound receptors.

3- The olfactory cortex is found in the temporal lobe receives information from odor receptors.

4- The gustatory cortex found in the insula and adjacent parts of frontal lobe receives information from taste receptors.

Cranial Nerves
Note: remember there are 12 cranial nerves. You should know all of them and their corresponding number in roman numerals. Example: the vagus nerve is the cranial nerve number X.

What is the function of the vestibulocochlear nerve?

= Carries sensory information for the senses of balance and equilibrium.

What is the function of cranial nerve I?

= The sense of smell.

What is the function of the hypoglossal nerve?

= Motor (tongue movements)

Pathologies and treatment

What are beta-blockers?

=They are drugs that are used to treat high blood pressure.

How is the frontal lobe of the brain affected by a stroke? Hint: learn the difference between what happens in the left and right side.

= A stroke in the frontal lobe impacts speech, language, reasoning:

Left Frontal Lobe: Affects speech, language, logical thinking, and personality.

Right Frontal Lobe : Affects spatial awareness, emotional regulation, and may cause neglect of the left side.

What is myopia?

= When the eye is elongated causing the image of near objects to come into focus in front of the retina.

What is astigmatism?

= Is a condition in which the light passing through the cornea and lens is not refracted properly and the visual image is distorted.