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EDU2EXP Exercise & Performance Neural, Muscular and Endocrine influences and adaptations to exercise.

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Presentation on theme: "EDU2EXP Exercise & Performance Neural, Muscular and Endocrine influences and adaptations to exercise."— Presentation transcript:

1 EDU2EXP Exercise & Performance Neural, Muscular and Endocrine influences and adaptations to exercise

2 EDU2EXP Exercise & Performance Reasons to study Cheating not tolerated  0 Will help you understand the remainder of course materials Won’t have as much catching up to do for final exam All students must pass all pieces of assessment in order to pass the subject

3 EDU2EXP Exercise & Performance Muscular Systems Chapter 1- p Chapter Pages are wrong in unit outline

4 EDU2EXP Exercise & Performance

5 contractual elements An I-band (light zone) An A-band (dark zone) An H-zone (in the middle of the A-band) An M-line in the middle of the H-zone The rest of the A- band A second I band

6 EDU2EXP Exercise & Performance Action Potential 1.A motor neuron releases acetylcholine (ACh) at the neuromuscular junction 2.ACh binds to receptors on the sarcolemma 3.If enough ACh binds to receptors, an action potential is transmitted the full length of the muscle fiber 4.The action potential triggers the release of Ca 2+ from the sarcoplasmic reticulum 5.Ca 2+ binds to troponin on the actin filament, and the troponin pulls tropomyosin off the active sites, allowing myosin heads to attach to the actin filament

7 EDU2EXP Exercise & Performance Muscle contraction- Sliding filament theory

8 EDU2EXP Exercise & Performance

9 Muscle fibre types

10 EDU2EXP Exercise & Performance Single Muscle Fiber Physiology Peak power is different between muscle fiber types All fiber types tend to reach their peak power at ~20% peak force Endurance training, strength training, and muscular inactivity may cause a shift in myosin isoforms – Exercise training ↓ type IIx and ↑ type IIa Aging may shift the relative distribution of type I and type II fibers – ↓ type II and ↑ type I

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12 Receptors Chemoreceptors- carry messages about O2 and Co2 concentrations, muscle pH, potassium Sensory feedback –Golgi tendon organs- give CNS feedback about tension developed in the muscle –Muscle spindles give feedback about length of the muscle

13 EDU2EXP Exercise & Performance Muscle spindles- length detector

14 EDU2EXP Exercise & Performance Adaptations Neural gains Muscle fiber hypertrophy- increase in size Muscle fiber hyperplasia- increase in number

15 EDU2EXP Exercise & Performance Hypertrophy 2 main types Transient- during and immediately after Chronic –Sarcoplasmic hypertrophy –Myofibrillar hypertrophy-

16 EDU2EXP Exercise & Performance Myofibrillar Hypertrophy Increased size/amounts of –Contractile proteins- Actin & Myosin –Myofibrals per muscle fibre –Connective tissue- ligaments etc –Enzymes & stored nutrients –mitochondria

17 EDU2EXP Exercise & Performance Microscopic Views of Muscle Cross Sections Before and After Training Photos courtesy of Dr. Michael Deschene's laboratory.

18 EDU2EXP Exercise & Performance Role of testosterone Acute increases after maximal exercise Anabolic effect Induces hypertrophy No relationship between total hypertrophy and testosterone

19 EDU2EXP Exercise & Performance Atrophy Muscle degeneration from disuse –Not synthesising new proteins –May be used as fuel Begins after 6 hours immobilisation Strength decreases of 3 to 4% per day More apparent with complete inactivity (bed rest) Effects are reversible

20 EDU2EXP Exercise & Performance Age related changes Sarcopenia –Slow phase- 10% loss from –Rapid phase- Extra 40% loss years –Therefore by 80, 50% muscle lost Predominant loss of fast fibres  slow ones

21 EDU2EXP Exercise & Performance Variability in adaptation Individual training responsiveness

22 EDU2EXP Exercise & Performance Genetics Myostatin- gene that inhibits muscle growth Therefore when this gene is inactive- extraordinary muscle growth occurs Some babies born with 1/ both myostatin genes inactive

23 EDU2EXP Exercise & Performance Belgian Blue cattle

24 EDU2EXP Exercise & Performance Muscle soreness Acute minutes or hours after exercise from accumulation of the end products of exercise in the muscles or edema Delayed 12 to 48 hours after a strenuous bout of exercise from eccentric muscle activity Is associated with: – Structural damage – Impaired calcium homeostasis leading to necrosis – Accumulation of irritants – Increased macrophage activity

25 EDU2EXP Exercise & Performance Delayed Onset Muscle soreness

26 EDU2EXP Exercise & Performance Muscle summary Muscle structure and function Muscle fibre types and adaptations Sliding filament theory Sensory –Muscle spindles –Golgi tendon organs Physiology of hypertrophy DOMS

27 EDU2EXP Exercise & Performance Neural Ch 3 pg 80-97

28 EDU2EXP Exercise & Performance Neuromotor System Organization Central nervous system (CNS) –Includes the brain and spinal cord Peripheral nervous system (PNS) –Is comprised of cranial and spinal nerves

29 EDU2EXP Exercise & Performance Neurotransmitters of the Brain Neurotransmitters- chemical messengers Synapse= gap between nerves

30 EDU2EXP Exercise & Performance Neuron Classifications Motor (efferent) neurons –Supply extrafusal and intrafusal skeletal muscle fibers Sensory (afferent) neurons –Transmit sensory information from peripheral sensory receptors to the brain

31 EDU2EXP Exercise & Performance Afferent Efferent

32 EDU2EXP Exercise & Performance Reflexes Sensory input Transmission of impulses to spinal cord via sensory root (afferent) Causes muscle fibres to contract (efferent)

33 EDU2EXP Exercise & Performance Autonomic Nervous System (ANS) Innervates smooth muscle (involuntary muscle) in the intestines, sweat and salivary glands, myocardium, and some endocrine glands Has two distinct divisions –Sympathetic –Parasympathetic

34 EDU2EXP Exercise & Performance Sympathetic Nervous System Sympathetic neurons –Exit the spinal cord and enter a series of ganglia (sympathetic chain) near the cord –Release norepinephrine Activated during flight-or- fight situations –Accelerates breathing and heart rate –Dilates pupils –Helps redistribute blood flow from the skin to deeper tissues in anticipation of a perceived challenge

35 EDU2EXP Exercise & Performance Neural Summary Generalised structure and function Reflex arcs ANS- Para and sympathetic

36 EDU2EXP Exercise & Performance Endocrine Chapter 2 page 59-76

37 EDU2EXP Exercise & Performance Hormones Steroidal Non steroidal

38 EDU2EXP Exercise & Performance Steroidal –Formed from cholesterol –Lipid soluble –Therefore can easily cross cell membrane walls To cell receptors inside cell cytoplasm/nucleus –Examples Adrenal cortex (cortisol and aldosterone) Ovaries (estrogen and progesterone) Testes (testosterone) Placenta (estrogen and progesterone)

39 EDU2EXP Exercise & Performance Nonsteroidal –Protein or peptide and amino acid-derived –Not lipid soluble  can’t cross cell membranes –Triggers a series of intracellular events through outside recepters Activates cellular enzymes Changes membrane permeability Promotes protein synthesis Changes cellular metabolism Stimulates cellular secretions Examples -Thyroid gland - Adrenal medulla (epinephrine and norepinephrine)

40 EDU2EXP Exercise & Performance Hormones of the Pancreas Insulin –Regulates glucose metabolism –Released in response to hyperglycemia –Facilitates glycogenesis (glucose  glycogen) Glucagon –Stimulates glycogenolysis –to release glycogen  blood glucose to prevent hypoglycemia

41 EDU2EXP Exercise & Performance

42 INSULIN- Controller of blood glucose levels

43 EDU2EXP Exercise & Performance Thyroid hormones Major endocrine gland Regulates metabolism Secretes non steroidal hormones –Increased protein synthesis –Increased mitochondria Failure to secrete thyroid hormones = hypothyroidism. Too much thyroid hormone = hyperthyroidism

44 EDU2EXP Exercise & Performance Hormones of the Adrenal Medulla Catecholamines Epinephrine (Adrenaline) (80%) Norepinephrine (20%) –Released during fight or flight response –Increase heart rate, contractility, and blood pressure –Rate of secretion is strongly influenced by exercise intensity Epinephrine increases after 50% vo2 max Norepinephrine increases after 60-70% vo2 max

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46 Cortisol “stress hormone” Important for fat and glucose metabolism regulation –Increases mobilisation of FFA’s  utilise for energy –Spare blood glucose and save for brain Decreased immune function

47 EDU2EXP Exercise & Performance Regulation of Glucose Metabolism During Exercise Glucose concentration during exercise is a balance between glucose uptake by the exercising muscles and its release by the liver –↑ Glucagon: promotes liver glycogen breakdown and glucose formation from amino acids –↑ Epinephrine: promotes glycogenolysis –↑ Norephinephrine: promotes glycogenolysis –↑ Cortisol: promotes protein catabolism

48 EDU2EXP Exercise & Performance Changes in Plasma Concentrations of Epinephrine, Norepinephrine, Glucagon, Cortisol and Glucose During 3 h of Cycling at 65% of VO 2max.

49 EDU2EXP Exercise & Performance Mechanism by which ADH Conserves Body Water

50 EDU2EXP Exercise & Performance Endocrine Summary Steroidal/Non steroidal hormones Thyroid hormones Pancreatic hormones: –Insulin & Glucagon Adrenal Hormones –Epinepherine –Norepinepherine –Cortisol And their roles during exercise


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