HNFE 1004 Ch. 3- Human Body: The Cell PDF

HNFE 1004 The Human Body: A Nutrition Prospective Dr. Angela Anderson  The cell Surrounded by the plasma membrane – Lipid bilayer containing phospholipids and cholesterol – Proteins involved in signaling, transport, enzymes are embedded in the PM Co...

HNFE 1004 The Human Body: A Nutrition Prospective Dr. Angela Anderson  The cell Surrounded by the plasma membrane – Lipid bilayer containing phospholipids and cholesterol – Proteins involved in signaling, transport, enzymes are embedded in the PM Contains cytosol & organelles  cytoplasm – Mitochondria – Nucleus – RER & SER – Golgi apparatus – Lysosomes – Peroxisomes Lipid Bilayer  Cholesterol Decreases fluidity  Smooth Endoplasmic Reticulum Synthesis of phospholipids, cholesterol, steroids, TAGs & glycogen Stores Ca++  Rough Endoplasmic Reticulum Proteins made at fixed ribosomes on the RER are released into the cisternae of the ER  Golgi Apparatus Modifies and packages proteins for secretion Produces lysosomes  Lysosomes Produced by the Golgi Apparatus Fuses with damaged organelles to break them down – Breaks down unused proteins Fuses with endosomes to destroy bacteria or other debris that enters the cell Autolysis- internal digestion of the cell Figure 3-8 Lysosome Functions (Part 1 of 2). Golgi apparatus Damaged organelle Autolysis liberates 3 1 Secondary digestive enzymes Primary lysosome lysosome 2 Reabsorption Reabsorption Endosome Secondary lysosome Extracellular solid or fluid Endocytosis Exocytosis Exocytosis ejects residue ejects residue  Peroxisomes Break down very long chain FAs Detoxify harmful chemicals Produce H2O2  Mitochondria Respiratory center of the cell – Contains the TCA cycle & electron transport chain Aerobic metabolism Part of a network  Nucleus Most cells contain 1 – Skeletal muscle has many – RBCs have none Contains nuclear pores for chemical communication Stores DNA – DNA is condensed into chromosomes – DNA is our genetic blueprint which is read by the enzyme RNA Polymerase, and produces mRNA Figure 3-10ab The Nucleus. Nucleoplasm Chromatin Nucleolus Nuclear envelope Nuclear pore a Important nuclear structures are shown here. Nuclear pore Perinuclear space Nuclear envelope b A nuclear pore is a large protein complex that spans the nuclear envelope.  Tissues Cells that work together to accomplish a specific task arrange themselves into tissues Humans have 4 tissues – Epithelial- covers all our surfaces including inside from mouth to anus – Connective- lies underneath epithelial tissue, supports & protects our body – Muscle- smooth, skeletal, heart – Nervous- nerves and supporting cells  Organs Tissues of all one type of different types come together to form a functional unit in the body called an organ Organs that work together for a particular function are called an organ system  Organ Systems: Integumentary Major Organs – Skin – Hair – Sweat glands – Nails Functions – Protects against environmental hazards – Helps regulate body temperature – Provides sensory information – Produces vitamin D  Organ Systems: Skeletal Major Organs – Bones – Cartilages – Associated ligaments – Bone marrow Functions – Provides support and protection for other tissues – Stores calcium and other minerals – Forms blood cells  Organ Systems: Muscular Major Organs – Skeletal muscles and associated tendons Functions – Provides movement – Provides protection and support for other tissues – Generates heat that maintains body temperature  Organ Systems: Nervous Major Organs – Brain – Spinal cord – Peripheral nerves – Sense organs Functions – Directs immediate responses to stimuli – Coordinates or moderates activities of other organ systems – Provides and interprets sensory information about external conditions  Organ Systems: Endocrine Major Organs – Pituitary gland – Thyroid gland – Pancreas – Adrenal glands – Gonads – Endocrine tissues in other systems Functions – Directs long-term changes in the activities of other organ systems – Adjusts metabolic activity and energy use by the body – Controls many structural and functional changes during development  Nutrition Related Hormones Other Hormones to know: – Secretin- Bicarbonate release from the pancreas – Gastrin- gastric motility; stomach enzyme release  Organ Systems: Cardiovascular Major Organs – Heart – Blood – Blood vessels Functions – Distributes blood cells, water, and dissolved materials including nutrients, waste products, oxygen, and carbon dioxide – Distributes heat and assists in control of body temperature Capillary Beds  Organ Systems: Lymphatic Major Organs – Spleen – Thymus – Lymphatic vessels – Lymph nodes – Tonsils Functions – Defends against infection and disease – Returns tissue fluids to the bloodstream Organ Systems: Respiratory Major Organs – Nasal cavities – Sinuses – Larynx – Trachea – Bronchi – Lungs – Alveoli Functions – Delivers air to alveoli (sites in lungs where gas exchange occurs) – Provides oxygen to bloodstream – Removes carbon dioxide from bloodstream – Produces sounds for communication  Organ Systems: Digestive Major Organs – Teeth – Tongue – Pharynx – Esophagus – Stomach – Small intestine – Large intestine – Liver – Gallbladder – Pancreas Functions – Processes and digests food – Absorbs and conserves water – Absorbs nutrients – Stores energy reserves  Organ Systems: Urinary Major Organs – Kidneys – Ureters – Urinary bladder – Urethra Functions – Excretes waste products from the blood – Controls water balance by regulating volume of urine produced – Stores urine prior to voluntary elimination – Regulates blood ion concentrations and pH  Organ Systems: Male Reproductive Male Major Organs – Testes – Epididymides – Ductus deferentia – Seminal vesicles – Prostate gland – Penis – Scrotum Functions – Produces male sex cells (sperm), seminal fluids, and hormones – Sexual intercourse  Organ Systems: Female Reproductive Female Major Organs – Ovaries – Uterine tubes – Uterus – Vagina – Labia – Clitoris – Mammary glands Functions – Produces female sex cells (oocytes) and hormones – Supports developing embryo from conception to delivery – Provides milk to nourish newborn infant – Sexual intercourse  What is metabolism? Life sustaining chemical reactions that occur in the cells of our body – What are macronutrients? – What is the life sustaining end product of macronutrient metabolism? Adaptation at its best – Physiological response to internal and external cues Short term and long term Anabolic vs. catabolic metabolism – Anabolic- to build/store Examples? – Catabolic – to breakdown Examples?  ATP Metabolism takes macronutrients (carbs, lipids, proteins) and makes ATP – ATP is the energy source that allows our body to do work ATP is made of an adenosine (adenine nucleotide plus a ribose sugar) and 3 phosphate groups (PO4)  Enzymes Type of protein Catalyze all chemical reactions in cells Speed up reactions, but are not consumed in the reaction Most enzymes are highly specific acting on a single substrate molecule or several substrate molecules Enzymatic reactions can be: – Equilibrium – Non-equilibrium Specificity of enzymes  Digestive System Food is broken down by mechani cal digestion and/or chemical digestion  Mouth Limited digestion – Salivary amylase Begins the digestion of carbohydrates – Lingual lipase Begins the digestion of lipids  Stomach Contains gastric pits (life of each cell is 3-7 days, then shed) – Parietal cells HCL & intrinsic factor – Low pH kills pathogens, denatures proteins, breaks down plant cell walls & animal CT, activation of pepsinogen to pepsin – Chief cells Pepsinogen (pepsin)- begins digestion of protein Gastric lipase- continues digestion of lipids – G cells (mostly in pylorus) Gastrin (hormone)- stimulates product release by the chief cells & parietal cells; and gastric motility – P/D1 cells (mostly in the fundus) Ghrelin (hormone)- initiates huger (secretion decreases shortly after eating) – Antagonistic to leptin, which is released from adipose tissue and signals satiety Stomach Anatomy  Small Intestine 90% of nutrient absorption occurs here (10% in LI) 3 parts – Duodenum- curves in a C Receives chyme from the stomach & digestive enzymes from the pancreas & liver – Jejunum Most of chemical digestion & absorption occurs here – Ileum Contains Peyer’s patches- protects the SI from bacteria from the LI Ends at ileocecal valve Contain villi that have microvilli (brush border) Small intestine Anatomy Small intestine Anatomy- Villi  SI enzymes & hormones Pancreatic Alpha amylase from the pancreas- continues carbohydrate digestion Pancreatic lipase- finishes lipid digestion Trypsin, Chymotrypsin, Elastase, Carboxypeptidase A&B from the pancreas as proenzymes (trypsinogen, chymotrypsinogen, proelastase, procarboxypeptidase A&B)- continues protein digestion Brush border enzymes finish the digestion of carbs & proteins – Sucrase, maltase, isomaltase, & lactase Finishes carbohydrate digestion – Aminopeptidase, tripeptidase, dipeptidylpeptidase Finishes amino acid (protein) digestion – Enteropeptidase- cleaves trypsinogen to trypsin (from pancreas) Hormones – CCK- pancreatic enzyme release & gallbladder contraction – Secretin- Bicarbonate release from the pancreas – Gastrin- gastric motility; stomach enzyme release  Pancreas Empties enzymes into the pancreatic duct, which joins the common bile duct & empties into the duodenal ampulla – Digestive enzymes, water, & ions Pancreatic alpha-amylase Pancreatic lipase Trypsinogen, chymotrypsinogen, procarboxypeptidase, & proelastase Pancrea s Anatom y  Liver physiology The liver carries out over 200 functions which fall into 3 categories: – Metabolic regulation Stable blood glucose Release & store FAs as needed Removes excess AAs  makes proteins or uses them to make glucose or store as FAs Urea cycle (removes nitrogen)  makes urea Storage of fat-soluble vitamins & B12 Stores iron Detoxification of drugs – Hematological regulation Phagocytosis by Kupffer cells (APC) & antigen presentation Synthesis of plasma proteins Absorption & recycling of E, NE, insulin, thyroid hormones, sex hormones, & corticosteroids Converts cholecalciferol to calcidiol Removal of antibodies Removal & breakdown of toxins – Bile production Synthesized from cholesterol  Function of Bile Emulsifies lipid droplets – Increases surface area of lipids so that enzymes can catabolize them Bile salts form micelles so that FAs can be absorbed by enterocytes 90% of bile salts are reabsorbed in the ileum, travel through the hepatic portal circulation back to the liver- enterohepatic circulation of bile  Gallbladder Stores & concentrates bile Releases bile when stimulated by CCK  Large intestine Stores wastes, reabsorbs water Resident bacteria produce some vitamins including Vitamin K, biotin, & pantothenic acid 3 parts: – Cecum – Colon – Rectum  Bacteria Foods can contain live microorganisms that will become part of the gut microbe population- Probiotics Prebiotics are substances that increase the growth of probiotic microorganisms Synbiotics- contain both probiotics and prebiotics Postbiotics are the metabolic products of probiotic microorganisms Gut bacteria and weight loss: Mayo Clinic Ra dio Colon Anatomy  Nutrition & Genetics Epigenetics- changes to gene expression without changing the DNA code – Ex. Methylating the promoter region so RNA polymerase can’t bind – PBS NOVA Epigenetics Nutritional genomics- interactions between genetics and nutrition – Nutrients have been found to be able to drive epigenetic changes  Common Problems with Digestion Heartburn/ GERD Peptic Ulcers Constipation Hemorrhoids Diverticulosis/Diverticulitis IBS (10-15% of adults; 2x more common in women) Diarrhea Gallstones Celiac Disease/ Gluten sensitivity