lecture exam 4 ( connect chapter summaries)

Muscles

Muscles

Organs made of cells specialized to generate forces.

Types of muscle tissue

Skeletal, smooth, and cardiac.

Structure of a Skeletal Muscle

Composed of nervous, vascular, and connective tissues, as well as skeletal muscle tissue.

Fascia

Connective tissue covering each skeletal muscle.

Skeletal muscle fibers

Cylindrical cells with many nuclei, containing mitochondria, sarcoplasmic reticulum, and myofibrils of actin and myosin.

Sarcomeres

Repeating patterns of striations formed by the arrangement of actin and myosin filaments.

Neuromuscular junction

Functional connection between a neuron and a muscle fiber.

Muscle fiber contraction

Results from a sliding movement of actin and myosin filaments overlapping, shortening the muscle fiber.

Excitation-contraction coupling

Process where stimulation causes the sarcoplasmic reticulum to release calcium ions, leading to the formation of cross-bridges between actin and myosin.

Oxygen debt

The amount of oxygen required to react accumulated lactic acid, restore ATP and creatine phosphate supplies after strenuous exercise.

Muscle fatigue

Loss of a muscle's ability to contract.

Isotonic contraction

Muscle contraction where the muscle shortens.

Isometric contraction

Muscle contraction where the muscle does not change length.

Smooth muscle

Contains filaments of myosin and actin, but not organized into myofibrils. Can change length without changing tautness.

Cardiac muscle

Contracts for a longer time than skeletal muscle due to transverse tubules supplying extra calcium ions.

Origin and insertion

The less moveable and more moveable ends of a skeletal muscle attachment to a bone, respectively.

Agonist

Muscle that causes a specific movement.

Antagonist

Muscle that resists a movement.

Synergist

Muscles that work together to perform a specific movement.

Major Skeletal Muscles

Muscles responsible for various movements in the body.

Life-Span Changes

Decline in supplies of ATP, myoglobin, and creatine phosphate, muscle mass reduction, and slowing reflexes with age.

Digestion

The process of mechanically and chemically breaking down foods so that they can be absorbed.

Alimentary canal

The long tube that extends from the mouth to the anus and is responsible for the processes of ingestion, propulsion, digestion, absorption, and defecation.

Mucosa

The innermost layer of the alimentary canal wall, responsible for secretion and absorption.

Submucosa

The layer of the alimentary canal wall that contains blood vessels, nerves, and glands.

Muscularis

The layer of the alimentary canal wall responsible for mixing and propelling movements.

Serosa

The outermost layer of the alimentary canal wall, providing protection and support.

Peristalsis

The coordinated contraction and relaxation of muscles in the alimentary canal wall that propels food forward.

Innervation

The supply of nerves to a specific area or organ.

Parasympathetic division

The branch of the autonomic nervous system that generally increases digestive activities.

Sympathetic division

The branch of the autonomic nervous system that generally inhibits digestive activities.

Cheeks

The lateral walls of the mouth.

Lips

Highly mobile structures that have sensory receptors useful in judging the characteristics of food.

Tongue

A thick, muscular organ that mixes food with saliva and moves it toward the pharynx.

Palate

The roof of the mouth, consisting of hard and soft portions.

Teeth

Structures that mechanically break food into smaller pieces, increasing the surface area exposed to digestive actions.

Salivary glands

Glands that secrete saliva, which moistens food, helps bind food particles, and begins chemical digestion of carbohydrates.

Pharynx

The passageway for food and air, divided into nasopharynx, oropharynx, and laryngopharynx.

Esophagus

The muscular tube that carries food from the pharynx to the stomach.

Stomach

The organ that receives food, mixes it with gastric juice, carries on a limited amount of absorption, and moves food into the small intestine.

Pancreas

An accessory organ closely associated with the duodenum that produces pancreatic juice containing enzymes for digestion and bicarbonate ions to neutralize chyme.

Liver

The organ located in the upper-right quadrant of the abdominal cavity that performs various functions, including detoxification, metabolism, and bile secretion.

Gallbladder

The organ that stores bile produced by the liver and releases it into the small intestine.

Small intestine

The portion of the digestive system that extends from the pyloric sphincter to the large intestine, where digestion is completed and absorption of nutrients occurs.

Large intestine

The portion of the digestive system that absorbs water and electrolytes and forms and stores feces.

Nutrients

Substances obtained from food that are necessary for growth, maintenance, and repair of body tissues.

Metabolism

The sum of all chemical reactions that occur in the body, including the breakdown and synthesis of molecules.

Carbohydrates

Organic compounds primarily used to supply cellular energy.

Lipids

Organic compounds that supply energy and are used to build cell structures, including fats, phospholipids, and cholesterol.

Triglyceride Metabolism

The liver and adipose tissue control the metabolism of triglycerides.

Fatty Acid Alteration

Liver enzymes have the ability to change the molecular structures of fatty acids.

Essential Fatty Acids

Linoleic acid and linolenic acid are essential fatty acids that must be obtained through the diet.

Cholesterol Regulation

The liver regulates cholesterol levels by either synthesizing or excreting it.

Lipid Requirements

The specific amounts and types of lipids needed for optimal health are currently unknown.

Wide Range of Lipid Intakes

Humans can survive with a wide range of lipid intakes.

Fat-Soluble Vitamin Absorption

Sufficient fat intake is necessary to support the absorption and transport of fat-soluble vitamins.

Protein Breakdown

Proteins are broken down during digestion, resulting in amino acids that can be used for various purposes.

Essential Amino Acids

Adults require 8 essential amino acids, while growing children require 10 essential amino acids.

Complete Proteins

Complete proteins contain adequate amounts of all essential amino acids needed for tissue maintenance and growth.

Incomplete Proteins

Incomplete proteins lack adequate amounts of one or more essential amino acids.

Nitrogen Balance

In healthy adults, the gain of protein equals the loss of protein, resulting in a nitrogen balance.

Positive and Negative Nitrogen Balance

Starving individuals have a negative nitrogen balance, while growing children, pregnant women, and athletes in training usually have a positive nitrogen balance.

Protein Requirements

Proteins and amino acids are needed to supply essential amino acids and nitrogen for various metabolic processes.

Energy Expenditures

Energy can be obtained from carbohydrates, fats, or proteins and is crucial for survival.

Energy Values of Food

The potential energy values of foods are expressed in calories, with carbohydrates and proteins yielding about 4 calories per gram and fats yielding about 9 calories per gram.

Factors Influencing Energy Requirements

Basal metabolic rate, muscular activity, body temperature, and nitrogen balance are factors that influence energy requirements.

Energy Balance

Energy balance occurs when caloric intake equals caloric output, resulting in weight maintenance. Positive energy balance leads to weight gain, while negative energy balance leads to weight loss.

Desirable Weight

Average weights of individuals aged 25-35 years are considered desirable for older individuals as well. Body mass index (BMI) is used to assess weight, with a BMI between 25 and 30 indicating overweight and above 30 indicating obesity.

Appetite Control

Appetite is the drive that compels us to eat, and hormones such as leptin and ghrelin play a role in controlling appetite.

Vitamins

Vitamins are organic compounds that are essential for normal metabolic processes and cannot be synthesized in adequate amounts by the body.

Fat-Soluble Vitamins

Fat-soluble vitamins are carried in lipids, resist heat effects, and include vitamins A, D, E, and K.

Vitamin A

Vitamin A is synthesized from carotenes, stored in the liver, and required for visual pigment production.

Vitamin D

Vitamin D is a group of related steroids, can be obtained from certain foods or synthesized in the skin, and promotes calcium and phosphorus absorption.

Vitamin E

Vitamin E is an antioxidant stored in muscles and adipose tissue, preventing breakdown of fatty acids and stabilizing cell membranes.

Vitamin K

Vitamin K is found in foods and produced by intestinal bacteria, stored in the liver, and used for blood clotting.

Water-Soluble Vitamins

Water-soluble vitamins include the B vitamins and vitamin C, are destroyed by cooking or food processing, and play various roles in metabolism.

Thiamine (Vitamin B1)

Thiamine functions as part of coenzymes that oxidize carbohydrates and synthesize ribose.

Riboflavin (Vitamin B2)

Riboflavin functions as part of enzymes and coenzymes essential for glucose and fatty acid oxidation.

Niacin (Vitamin B3)

Niacin functions as part of coenzymes required for glucose oxidation and protein and fat synthesis.

Pantothenic Acid (Vitamin B5)

Pantothenic acid functions as part of coenzyme A, essential for energy-releasing mechanisms.

Vitamin B6

Vitamin B6 functions as coenzymes in metabolic pathways for protein synthesis and amino acid production.

Biotin (Vitamin B7)

Biotin is a coenzyme required for amino acid and fatty acid metabolism and nucleic acid synthesis.

Folacin (Vitamin B9)

Folacin is a coenzyme needed for amino acid metabolism, DNA synthesis

calat-

something inserted; intercalated disc-membranous band that connects cardiac muscle cells

erg-

work; synergist-muscle that works with a prime mover, producing a movement

fasc-

bundle; fasciculus-bundle of muscle fibers

-gram

something written; myogram-recording of a muscular contraction

hyper-

over, more; muscular hypertrophy-enlargement of muscle fibers

inter-

between; intercalated disc-membranous band that connects cardiac muscle cells

iso-

equal; isotonic contraction-contraction during which the tension in a muscle remains unchanged

laten-

hidden; latent period-period between a stimulus and the beginning of a muscle contraction

-lemm

rind or peel; sarcolemma-the cell membrane of a muscle fiber

myo-

muscle; myofibril-contractile bundle of filaments within a muscle cell

reticul-

a net; sarcoplasmic reticulum-network of membranous channels within a muscle fiber

sarco-

flesh; sarcoplasm-substance (cytoplasm) within a muscle fiber

syn-

together; synergist-muscle that works with a prime mover, producing a movement

tetan-

stiff; tetanic contraction-sustained muscular contraction

-tonic

stretched; isotonic contraction-contraction during which the tension of a muscle remains unchanged

-troph

well fed; muscular hypertrophy-enlargement of muscle fibers

aliment-

food; alimentary canal-tubelike part of the digestive system