Study Quide Lecture Exam #2 Flashcards
- Describe detailed structure of skeletal muscle: connective tissue components, fibers, myofibrils, sarcomeres, thick and thin filaments components.
Sarcomere -> Myofibrils -> Muscle fibers (surrounded by endomysium) -> Fascicles (surrounded by perimysium) -> Skeletal Muscle (surrounded by epimysium)
Thick filaments: myosin, longtail with globular heads. Release energy for contraction
Thin filaments: four proteins Actin (G actin), tropomyosin, troponin, nebulin
Sarcoplasmic reticulum
Storage and release site for calcium ions
Sarcomere
Repeating unit of a skeletal muscle fiber
Thin filaments
Consist of G actin, troponin, tropomyosin, nebulin
Thick filaments
Acts as ATPase during contraction cycle
Myosin head
Consist of myosin molecules
Troponin
Binds to calcium and moves tropomyosin
Epimysium
Dense layer of CT that surrounds entire skeletal muscle.
Skeletal muscle triad
Transverse tubule and two terminal cisternae
Myoglobin
Oxygen-binding protein found in the muscle tissue
Tropomyosin
Preventing interactions between actin and myosin
Role of ATP in muscle contraction and relaxation
a. ATP in muscle contraction and relaxation disconnects myosin cross bridge from actin; responsible for cocking (pulling back) the myosin head, ready for another cycle; provides energy for active transport of Ca2+ back into SR; Maintains RMP of the skeletal muscle cells.
What is role of Calcium in muscle contraction?
Binds to troponin, which activates troponin-tropomyosin complex.
Rigor mortis: explain why stiffness of the body occurs shortly after death.
This occurs because skeletal muscles partially contract and are unable to relax. (The joints are fixed, and the body stiff)
How energy is supplied for contraction.
The energy is provided through energy (cellular) metabolism.
Events in order of a muscle contraction
Calcium ion is released from the sarcoplasmic reticulum
Calcium ion binds to troponin
Myosin cross-bridges bind to the actin
The myosin head pivots toward the center of the sarcomere
The myosin head binds an ATP molecule and detaches from the actin
The free myosin head splits ATP
Somatic vs autonomic nervous systems
Somatic- voluntary and involuntary, effects skeletal muscles, one lower motor neuron. No stops only to one location.
Autonomic- only involuntary/visceral reflexes autonomic reflexes, effects smooth muscle, cardiac muscle, and glands, 2 lower motor neurons
Parasympathetic
increase digestion, decrease Heart rate/ blood pressure, bronchonstriction, pupil contr. Sacralarea of s2-s4 spinal cord. Ganglia close to targe organ. Paraganglia- long, postganglionic- short.
Sympathetic
inhibit digestion, increase heart rate/ blood pressure, vasoconstriction/vasodilation, bronchodilation, pupil dilation. Lateral horn of SC T1-L2. Ganglia- close to CNS. Preganglionic- short. Postganglionic- long.
Nicotinic receptor
found on all ganglionic neurons and adrenal medulla. Always excitatory.
Muscarinic
all target membranes in parasympathetic division. Could be excitatory or inhibitory
Cholinergic
nicotinic (excitatory)/ muscarinic (excitatory or inhibitory) (parasympathetic)
Adrenergic
Alpha- 1 & 2: vasoconstriction (excitatory/inhibitory), Beta- 1 (always excitatory, heart, increase heart rate), 2 (always inhibitor, bronchioles, vasodilation of skeletal muscle), 3 (adipose tissue)
Beta 1
always excitatory, heart, increase heart rate
Beta 2
always inhibitor, bronchioles, vasodilation of skeletal muscle
Beta 3
adipose tissue
Describe possible effects of beta blockers (medication that blocks beta receptors), medication that is used to decrease blood pressure
Decrease heart rate, bronchoconstriction, vasoconstriction of skeletal muscle.
Explain why atropine (medication that blocks muscarinic receptors) will cause tachycardia, dry mouth, constipation, increased blood pressure, and dilated pupils.
Atropine will cause tachycardia, dry mouth, constipation, increased blood pressure, and dilated pupils (sympathetic nervous system effects), because by blocking the muscarinic receptors it will decrease the parasympathetic nervous system causing an increase in the sympathetic nervous system.
Nervous system
wired, neurotransmitters, limited distance, rapid response, short duration, rapid onset.
Endocrine system
wireless, hormones, long distance, regulation, prolonged duration, delayed onset.
Describe how production of hormones is regulated in our body
a. Negative feedback process.
b. A stimulus elicits the release of a substance (hormone) -> once the substance (hormone) reaches a certain level, it sends a signal that stops further release of substance -> in this way, the concentration of hormones in blood is maintained within a narrow range.
List functions of endocrine system
a. Maintain homeostasis of blood composition and volume
b. Controlling reproductive activities
c. Regulating development, growth, and metabolism
d. Controlling digestive processes
Thyroid and calcium
Thyroid (c-cells)- calcitonin decreases calcium level builds bones by activating osteoblasts and inhibiting osteoclasts.
Parathyroid gland and calcium
Parathyroid gland- Parathyroid hormone- calcium increases- destroy bones- activates calcitriol.
Kidney and calcium
Kidney- calcitriol- enhances PTH- enhances Ca2+, PO43- absorption by digestive system.
Lipid-soluble: steroid hormone
lipid-soluble, formed from cholesterol, produced by gonads and adrenal cortex. Cortisol, estrogen, and testosterone.
Water-soluble (except thyroid hormone): protein hormone
water soluble, amino acid chain, 3 sub groups- polypeptides, oligopeptides, glycoproteins. Parathyroid hormone, insulin
Water-soluble (except thyroid hormone): biogenic amine
water-soluble (excluding thyroid hormone), derived from amino acid that is modified (e.g. tyrosine). Norepinephrine, melatonin, T3 and T4.
Glucose is decreased by
insulin which is produced by the pancreas, it is regulated by blood glucose level.
Glucose is increased by
glucagon (pancreases), cortisol (zona fasciculata of adrenal gland), growth hormone (released by hypothalamus), and epinephrine (adrenal medulla of adrenal gland)
Describe how water balance is regulated by endocrine system.
Antidiuretic Hormone (vasopressin) plays an important part in regulating water, it does so by reduced urine volume and cause water retention.
Describe how nervous and endocrine systems maintain arterial blood pressure.
a. ADH increases blood pressure.
b. Atrial Natriuretic Peptide reduces blood pressure.
c. Blood pressure is increased during sympathetic autonomic nervous system.
d. Blood pressure is decreased during parasympathetic autonomic nervous system.
