Muscle Final Exam Study Guide PDF

Muscle (new material) ​ Length - Tension Relationship ○​ The length tension relationship refers to the amount of tension a sarcomere can generate. There is an optimal length at overlap in a sarcomere between the actin and myosin filaments that will produce the m...

Muscle (new material) ​ Length - Tension Relationship ○​ The length tension relationship refers to the amount of tension a sarcomere can generate. There is an optimal length at overlap in a sarcomere between the actin and myosin filaments that will produce the most tension. If they are not overlapped enough there is nothing for the myosin heads to bind to, to then make a powerstroke. On the flip side, when they are too overlapped, there are fewer myosin heads that can interact with the actin filaments. So, cross bridges cannot form as well. Both of these scenarios make it so there is not enough force and tension to make a contraction. This is why you need a happy medium in the middle where the length of overlap is not too much, and also not too little. ​ Twitches ○​ A twitch is the cycle of contraction and relaxation when a muscle is directly stimulated with an electrode. A twitch consists of a stimulation, latent period, contraction phase, and a relaxation phase. A muscle twitch occurs at a low status frequency. Pg. 1 (know what the latent period looks like on the diagram) ​ Strength of twitches and recruitment of fibers ○​ A stimulus must reach a threshold for nerve fibers to be activated to make a twitch happen to then become contractions. Twitches are the building blocks for a contraction for a contraction. There are two things that affect a muscle twitch and contraction: intensity (voltage) and frequency. Intensity refers to the amount of nerve fibers activated during a twitch/contraction. Frequency refers to the frequency of stimuli in a contraction. Which I will explain in the next question. Since there is a threshold that the strength of the stimulus has to reach, there could be times when a stimulus is small enough that the threshold is not hit, therefore no nerve fibers are excited, and no contraction occurs. Once the threshold is hit, the larger the stimulus, the more nerve fibers are excited, to create larger and larger contractions.  ​ Twitches: the building blocks for a contraction. ​ Tetanus ○​ Whether or not a tetanus occurs depends on the amount and frequency of a stimulus to a nerve. When there is a low stimulus frequency, a regular sequence of twitches occurs. The Twitches have time to fully relax back to where they started from when the stimulus happened. This creates a regular pattern, that if you drew a line connecting the Peaks at every twitch, the line would be straight. However, in an incomplete tetanus, the twitch doesn't have enough time to fully relax before the next stimulus, so the muscle tension is overall climbing an upwards path. If you were to draw a line connecting all the Peaks you would have a line with a positive slope. This is called temporal summation because all these twitches are building off one another and creating even bigger muscle tension and contractions. For complete, or fused, tetanus there is an unnaturally high stimulus frequency. In complete tetanus, it starts out as what incomplete tetanus looks like, but then the muscle tension reaches a threshold that makes the maximum muscle tension, so the spikes level off. If you were to draw a line connecting all the peaks you would draw what looks like a square root graph that eventually levels off. Even though complete tetanus and a normal twitch both end in a straight line, they are different because the complete tetanus line is much higher and has a greater muscle tension. ​ Pg. 4 incomplete tetanus and complete tetanus diagrams. ​ Sources of energy for muscle fibers and exercise -​ There are three systems / ways for muscle fibers to get energy. Phosphagen System: Does not require O2, has a 10-15 second duration, when you use it you use it in short bursts of intense activity (Sprinting, heavy lifting), has no by-products, its efficiency is very fast but not long lasting. Anaerobic Respiration or Fermentation: Does not require O2, has a 15 second - 2 minute duration, when you use it you use it in intense short duration activities (sprinting, lifting), the by-products are lactic acid (makes muscle sore), its efficiency is fast but less efficient. Aerobic Respiration: Requires O2 (this is why you breath so heavy at certain points when running), the duration is minutes - hours, you use it during low to moderate intensity activities (jogging, cycling, swimming), the by-products are carbon dioxide (CO2), heat (body heat), and water (sweat and water vapor when you breath), it is slow but highly efficient. Creates 36 ATP for the body. ​ Myasthenia Gravis and Muscular Dystrophy -​ Myasthenia Gravis is drooping eyelids and weakness of muscles of the eyes. -​ Muscular Dystrophy is the overall general weakening of muscles. There is no cure, but medications and physical therapy can alleviate symptoms. ​ Basic Muscle Anatomy (Sarcomere, Myofibril, Muscle Fiber, etc…) ○​ Muscle → Fascicle → Muscle Fiber → Myofibrils → Sarcomere → Myofilaments ○​ The Sarcomere is the contractile unit of a myofibril. See picture on page 5. -​ I-band: Contains only thin filaments. -​ A-band: Contains thick and thin filaments. -​ Z disc: Anchors the thin filaments. -​ Elastic (titin) filaments: Springy and brings back to shape after a contraction. -​ Thin filaments: Made of myosin. -​ Thick filaments: Made of actin. Associated with the proteins troponin and tropomyosin. (know how to label a thin filament pg.5) ​ A myofibril contains many, many sarcomeres. It is a bundle of protein myofilaments within a muscle fiber, which fills most of the cytoplasm. Has a banded appearance because of the overlap of thick and thin filaments. ​ A muscle fiber is a single muscle cell. It’s enclosed in a sarcolemma membrane and contains myofibrils, nuclei, sarcoplasmic reticulum, and it is enclosed in the endomysium.  ​ Types of muscle fibers and their uses (fast, slow, glycolytic) ○​ There are different muscle fiber types within each muscle. These are called slow oxidative, fast oxidative, and fast glycolytic. Fast oxidative fibers aren’t really prevalent in humans. Unless you train a lot though. Slow oxidative fibers are better for endurance and fast glycolytic is better for things like sprinting. Pg. 6 for pictures. -​ Slow Oxidative Fibers: -​ Speed of Contraction: Slow -​ Strength of Contraction: Weak -​ ATP Production: Aerobic Respiration -​ Fatigue: Slowly -​ When to use it: Endurance Activity -​ Fast Glycolytic Fibers: -​ Speed of Contraction: Fast -​ Strength of Contraction: Strongest -​ ATP Production: Glycolysis or Anaerobic Respiration -​ Fatigue: Quick -​ When to use it: Fast, powerful movements -​ Fast Oxidative Fibers: -​ Speed of Contraction: Fast -​ Strength of Contraction: Strong -​ ATP Production: Glycolysis and Aerobic Respiration -​ Fatigue: Slowly -​ When to use it: Walking, not in humans * Every muscle has a mix of all muscle fibers, but usually one is predominant over the others depending on the muscle function. * Fiber types differ from person to person and are genetic. ​ Excitation - Contraction Coupling (contraction of muscles) ○​ Thin Filament - Actins role -​ In order for actin to bind to myosin, the active binding sites in actin have to be exposed. Tropomyosin is covering the active  binding sites and has to roll out of the way with the help of troponin. The action potential of this releases calcium ions (Ca2+) which control the timing of the reactions. Now, since the active binding sites are exposed, the myosin heads can come in and form a cross bridge to the actin. ○​ Thick Filaments - Myosins role -​ An ATP binds to a myosin head. This ATP is hydrolyzed and reacts to become ADP + Pi. The energy released from this is used to cock the myosin head into place to form a cross bridge. Even though the myosin head moved, the ADP and Pi are still attached to the myosin head. Actin and a myosin head are now connected by a cross bridge between an active binding site on actin and a myosin head. While connected, myosin releases the ADP + Pi which causes a powerstroke. A powerstroke is what it is called when the power from ADP + Pi release, causing the myosin head to cock back into the golf club shape. This movement pulls the actin filament with it causing the actin to move. Then, after the powerstroke the cross bridge breaks, and the myosin head finds a new ATP to bind to to start the whole process over again. ​ Structure of a Sarcomere/Myofibril related to function ○​ Sarcomere: A sarcomere is the basic unit of a muscle contraction. ○​ Actin + Myosin → work together to shorten filaments. -​ Z disc → moves closer to each other -​ H zone → shrinks -​ I band → shrinks -​ A band → stays the same length -​ M line → anchors the myosin filaments *All of this works together to provide movement of a muscle fiber whether it is a short twitch or a sustained contraction. ​ Differences in Smooth/Skeletal/Cardiac Muscle ○​ Skeletal Muscle:  -​ Cells fuse to form fibers -​ Striated -​ Voluntary -​ Other Structures -​ (Myofibrils, Sarcolemma → t-tubule, nuclei, mitochondria, triad structure (t-tubule + sarcoplasmic reticulum)) ○​ Cardiac Muscle: -​ One nuclei per cell -​ Striated, branched -​ Involuntary -​ Intercalated discs ○​ Smooth Muscle: -​ Non-striated -​ Involuntary -​ Lines blood vessels, glands, digestive tract Nervous (new material) ​ Ascending/descending pathways (type of info, synapses, crossing of info for sensory inputs) Ascending: ○​ Posterior Column Medial Lemniscus Pathway: ​ When does your body use it? -​ Fine touch -​ Pressure -​ Proprioception (body position) -​ First order neuron: The cell body of a first order neuron is located in the dorsal root ganglion. Synapse: medulla. -​ Second order neuron: The cell body of the second order neuron is located in the medulla, then crosses over (decussates) at medulla and shoots up through the midbrain. Synapse: thalamus.  -​ Third order neuron: The cell body of the third order neuron is located in the thalamus. Synapse: to the prime somatosensory cortex. Pg. 9 picture. Know where the second motor neuron decussates. Ascending: ○​ Anterolateral Pathway: ​ When does your body use it? -​ Pain -​ Temperature -​ First order neuron: The cell body is located in the dorsal root ganglion. Synapse: dorsal horn of spinal cord. -​ Second order neuron: The cell body is located in the dorsal horn of the spinal cord, decussates in spinal cord. Synapse: Thalamus. -​ Third order neuron: The cell body is located in the thalamus. Synapse: Somatosensory cortex. Pg. 10 picture. Know where the second order neuron decussates. *Differences between posterior column medial lemniscus and anterolateral: -​ Decussates is in medulla for posterior column medial lemniscus -​ Decussates is in spinal cord for anterolateral Descending: ​ Corticospinal Pathways: ○​ Lateral corticospinal pathway: ​ When does your body use it? -​ Limbs (appendicular skeleton) -​ Moves muscles -​ Writing, playing instruments, etc… ○​ Anterior corticospinal pathway: ​ When does your body use it? -​ Axial skeleton  -​ Moves muscles -​ Trunk flexion, hip movement, etc… Lateral Corticospinal Pathway: -​ First motor neuron: Primary motor cortex -​ Decussate: Medulla -​ Synapse: Spinal Cord -​ Second order neuron: Spinal Cord Anterior Corticospinal Pathway: -​ First motor neuron: Primary motor cortex -​ Decussate: Spinal cord -​ Synapse: Spinal cord -​ Second order neuron: Spinal cord Pg. 11 picture. Know where each one decussates. ​ Disorders eg. Parkinsons, bells palsy, etc. (relating behavioral changes to an underlying neurological change) Parkinsons: ○​ The dopamine-producing cells die which leads to problems with movement. The substantia nigra shrinks overtime, making it hard to control movement. ○​ Symptoms: Tremor, shuffling walk, trembling of the head and extremities, reduced arm swinging. Bell's Palsy: ○​ The cold sore stand of Aids (HSV-1) infection paralyzes the facial nerve. This causes one side of the face to droop. Will go away/get better in the span of months. Can be hard for someone to know whether it is bell's palsy or a stroke. ALS: ○​ The degeneration of the upper and lower motor neurons. The upper motor neurons are located in the brain And send signals to the spinal  cord. The lower motor neurons are located in the spinal cord and send signals to the muscles. In ALS, a person slowly loses control of all muscles in their body. There is no cure and a patient would have 7 to 10 years to live after diagnosis. ​ Meninges (relate them to a function/procedure. Ex. lumbar puncture, epidural, etc…) ○​ The meninges of the brain or the three protective layers between the brain and the skull. the meninges or the dura mater, arachnoid mater, and pia mater. The meninges protect the brain and spinal cord from physical damage. The arachnoid mater and pia mater form a space for cerebrospinal fluid. To relate meninges to a procedure like Lumber puncture or a spinal tap, you should know what a lumbar puncture is. A lumbar puncture is when a doctor inserts a needle in the lumbar vertebrae region to collect cerebrospinal fluid red minister medications. During the spinal tap, the needle passes through the Durham water to reach the arachnoid and PM model, which is where the cerebrospinal fluid is. The spinal tap is done to diagnose conditions like meningitis, ms, or cancer. It is also used for administering medications like chemotherapy for brain cancer/spinal cord cancer. An epidural is a procedure usually given to pregnant women in labor or surgery to aid in pain relief. A needle filled with the pain medication is inserted into the epidural space, which is right outside the dura mater. None of the meninges are punctured during this procedure. The medicine blocks pain signals from the spinal cord to the brain. ​ Ventricles and Flow of CSP ○​ Structures: -​ Choroid Plexus → Makes CSF -​ Lateral Ventricle -​ Third Ventricle -​ Fourth Ventricle  1.​ Cerebrospinal fluid is secreted by the choroid plexus in the lateral ventricle. 2.​ The CFS flows to the third ventricle. 3.​ The choroid plexus in the third ventricle adds more CSF to the flow. 4.​ CFS flows to the fourth ventricle. 5.​ Choroid plexus in the fourth ventricle adds more CSF. 6.​ CSF flows out of lateral and median apertures. 7.​ CSF fills subarachnoid space. or 8.​ CSF flows to arachnoid granulations and is reabsorbed into venous blood. ​ Divisions of the PNS (autonomic, somatic), and CNS Pg. 14. Know the picture. -​ Autonomic Nervous System: Involuntary responses. -​ Sympathetic Division: Fight or flight response -​ Parasympathetic Division: Rest and Digest ​ Connections of the sympathetic ganglia / neurotransmitters used Pg. 15. Memorize all pictures. ​ Reflex Arcs ○​ There are three different reflex arcs we need to know: The basic reflex arc, patellar reflex, and reciprocal inhibition of antagonistic muscle, and the flexor and crossed extensor reflex arc. Basic Reflex Arc: -​ Pg. 16 Pictures. *Importance of the interneuron: Can talk to multiple cells at once, and can switch from excitatory to inhibitory. ​ Functions of brain areas / hemispheres (eg. lateralization, also primary sensory/motor cortices, which also does what, and where is it) ○​ Left Hemisphere: -​ Language -​ Logical reasoning ○​ Right Hemisphere: -​ Creativity -​ Spatial awareness -​ Emotion processing ○​ Frontal Lobe: -​ Inhibiting inappropriate impulses -​ Control -​ Mood -​ Speech production -​ Explicit memory -​ Abstract thought ○​ Insula: -​ Processing of pain -​ Gut related visceral sensation -​ Taste -​ Emotion + Empathy -​ Cardiovascular homeostasis ○​ Parietal Lobe: -​ Taste -​ Somatic sensation -​ Visual processing -​ Sensory integration ○​ Occipital Lobe: -​ Visual processing -​ Visual awareness  ○​ Temporal Lobe: -​ Hearing -​ Smell -​ Emotion -​ Learning -​ Language comprehension -​ Memory Receptive Fields: -​ One large receptive field can feel pain/touch less than 3 smaller receptive fields. Overarching Topics ​ Homeostasis ○​ The body's way of regulating itself. Homeostasis is the equilibrium our body is trying to get to at all times either through positive or negative feedback loops. ​ Positive Feedback ○​ Positive feedback is when your body is pushing more toward the direction of the change, leading to a large change. After the large change your body can go back to homeostasis. Example. Action potential, childbirth. ​ Negative Feedback ○​ Fluctuating back and forth up and below the equilibrium or homeostasis line. An example would be when you get hot you start to sweat which cools you down, then you are too cool so you start to get hotter and so on. Membranes ​ Transport Mechanisms -​ Passive diffusion → high to low (no energy) -​ Facilitated diffusion → high to low (no energy) large molecule -​ Osmosis → water diffuses to an area of high solute -​ Active transport → low to high (needs ATP)  -​ Coupled transport → teamwork with active transport -​ Bulk transport: endocytosis -​ Pinocytosis: Cell drinking -​ Phagocytosis: Cell eating -​ Exocytosis → removes waste ​ Hydrophobic / Hydrophilic ○​ Hydrophobic → water fearing ○​ Hydrophilic → water loving -​ Example: Phospholipid. Tail is hydrophobic and the head is hydrophilic. Macromolecules ​ Levels of Protein Structure (maybe worked into a membrane question) ○​ Proteins are made up of amino acids. proteins have four different types of structures. primary, secondary, tertiary, quaternary. Primary is a chain of amino acids. secondary is when they start to make bonds, alpha helices and beta sheets. tertiary is functional and 3d, quaternary is all of these mixed together. ​ Lipids and Bilayer (maybe worked into a membrane question ○​ The phospholipid bilayer is selectively permeable and makes up most membranes of the cell. It contains an outer and inner leaflet of lipids because of water interaction. Nervous ​ Resting Potential ○​ Before an action potential happens  ​ Parts of an Action Potential and what is doing stuff at each part -​ Pg. 20. Memorize this picture and write it on the page before your exam starts. ​ Synaptic Signaling ○​ Calcium causes vesicles of neurotransmitters to bind to the presynaptic membrane. Neurotransmitters cross the synapse and bind to the receptors on the post synaptic vesicle. This causes local Potentials in the target cells. If enough local potentials occur, through summation an action potential can happen. -​ Pg. 20 Memorize pictures and know what is happening. Bones ​ Intramembranous and Endochondral Ossification ○​ Intramembranous → fetal bone development ○​ Endochondral → bone growth in length for children ○​ Length = Interstitial (elongation) ○​ Width = Oppositional ​ Calcium homeostasis/negative feedback/blood Ca2+ levels and the 3 hormones. How do they work? ○​ Calcium homeostasis refers to the idea that calcium in our blood and bones fluctuate. Hypercalcemia is when there is too much calcium in the blood, so it gets deposited into our bones. Hypocalcemia is when our body does not have enough calcium, so our body takes calcium from the bones because the blood needs it in order to move. Calcium homeostasis depends on what you eat/drink, and relies heavily on hormones. These hormones are calcitonin, which tones it down, calcitriol, and PTH which both increase calcium levels in blood. Integumentary System ​ Skin Cancer, Cell types, and layers of skin 1.​ Corneum → Keratinocytes 2.​ Lucidum → Keratinocytes 3.​ Granulosum → Dendritic, keratinocytes 4.​ Spinosum → Dendritic, keratinocytes 5.​ Basale → Stem cells, tactile, keratinocytes, melanocytes -​ Basal Cell Carcinoma: Fine -​ Squamous Cell Carcinoma: Not Good -​ Malignant Melanoma: Fatal DNA ​ What and Where - Transcription vs. Translation ○​ Transcription —> Nucleus, making DNA to RNA ○​ Translation —> Cytoplasm, making mRNA to protein Cell Cycle ​ Homologous Chromosomes vs. Sister Chromatids Pg. 22 ( memorize pictures ) ​ Checkpoints of Cell Cycle ○​ G1 → Checkpoint before DNA is copied ○​ S → COPYING correctly ○​ G2 → Did it copy correctly (checking)  ​ Cancer happens because the G2 phase gets skipped or it is not done correctly ○​ M → Mitosis, are they lined up for division Glucose Catabolism ​ Where is the most ATP generated? 4 Processes we talked about. 1.​ Glycolysis → Cytosol a.​ Products: 2 ATP, 2 NADH, 2 Pyruvate 2.​ Oxidation of Pyruvate → Mitochondria a.​ Products: 2 COA, 2CO2, 2 NADH 3.​ Krebs Cycle (the citric acid cycle) → Mitochondrial Matrix a.​ Products: 6 NADH, 4 CO2, 2 FADH2, 2 ATP 4.​ Electron Transport Chain → Inner mitochondrial membrane a.​ Products: 25 ATP -​ Grand Total = 32 ATP