Physiology No 1

‫بســـم الله الرحمن الرحيم‬

‫المحاضرة‬ ‫الولى‬ ‫من صـــفحة ‪20‬‬ ‫الى صــفحة ‪36‬‬

PHYSIOLOGY Nutrition ‫ة‬ ‫التغـﺫي‬ Series Processes Takes in Assimilate Promote growth Replace worn tissues

‫سلسلة‬ ‫عمليات‬ ‫يأخـﺫ‬ ‫يمثل الطعام‬ ‫تعزيز أو تشجيع النمو‬ ‫استبدال النسجة التالفة أو البالية‬

Animal nutrition: It is a series of processes by which an animal takes in & assimilates the various food substances needed to promote growth & replace worn tissues.

Types of organisms Autotrophs Phototrophs Chemotrophs Heterotrphs Saprozoic Parasites

‫ﺫاتى التغـﺫية‬ ‫الغتـﺫاء الضوئى‬ ‫الغتـﺫاء الكيميائى‬ ‫غير ﺫاتى التغـﺫية أو مختلف التغـﺫية‬ ‫يعيش على الرمم أو رمى التغـﺫية‬ ‫طفيليات‬

Autotrophs: -1that can synthesize all essential organic compounds from inorganic sources. They include: A-Phototrophs: the chlorophyll-containing green plants. B-Chemotrophs .: the chemosynthetic bacteria Heterotrophs: -2that require an intake of organic compounds asmost animals. Saprozoic:that can absorb large organic molecules through body surfaces asa few animals. These animals are .primarily parasites

Nutrition in mammals Mammals ‫الثدييات‬ Nutritional requirements ‫المتطلبات الغـﺫائية‬ Minerals ‫المعادن‬

* Heterotrophic. * The nutritional requirements of mammals can be divided into: 1- Organic materials: such as carbohydrates, lipids and proteins. 2- Vitamins 3- Inorganic nutrients such as minerals.

Carbohydrates -1

Derivatives Hydrolyzed Constituents Glycosidic bonds Hydrolysis

‫مشتقات‬ ‫ينحل مائيا‬ ‫مكونات‬ ‫روابط جليكوسيديه‬ ‫انحلل مائى‬

It is aldehyde or ketone derivatives of the polyhydric (more .than one OH group) alcohols They are classified into: 1- Monosaccharides (simple sugars): which can not be hydrolyzed into simpler forms. They may be subdivided (according to the number of carbon atoms) into: A- Trioses (3-carbon sugars). B- Tetroses (4-carbon sugars). C- Pentose (5-carbon sugars) such as ribose & deoxyribose which are the main constituents of nucleic acids (DNA & RNA). D- Hexoses (6-carbon sugars) such as glucose, fructose, galactose & mannose which are physiologically the most important. .Till we reach 10-carbon sugars

Disaccharides (double sugars): They are composed of 2 -2 molecules of monosaccharides which are united by a glycosidic bonds. Sucrose, maltose & lactose are the most common .disaccharides 3- Polysaccharides (complex sugars): which on hydrolysis yield more than 6 molecules of monosaccharides. Glycogen, starch, cellulose, dextrins, inulin & chitin are the most common polysaccharides. Glycogen * It is the storage polysaccharide in the animal body. ** It is found in high amounts in liver & muscle. *** It is called animal starch.

Lipids -2 Lipids Solvents Waxes Derived lipids Energy Major constituents

‫دهون‬ ‫مـﺫيبات‬ ‫شموع‬ ‫الدهون المشتقة‬ ‫طاقة‬ ‫مكونات رئيسية‬

Lipids have a common character which is being soluble in fat .solvents They are classified into: 1- Simple lipids: They are esters of fatty acids with various alcohols.They include: .A- Fats: Esters of fatty acids with glycerol R1-COOH + R2-COOH + R3-COOH fatty acids 3

+

HO-CH2

R1-COO-CH2

OH- CH

R2-COO-CH

OH-CH2 Glycerol

R3-COO-CH2 Fat

N.B. A fat in the liquid state is known as an oil. B- Waxes: Esters of fatty acids with monohydric alcohols with .higher molecular weight

Compound lipids: e.g. phospholipids -2 & glycolipids (carbohydrate-attached lipids). 3- derived lipids: These are substances derived from simple or compound :lipids on hydrolysis such as

Phospholipids

.Fatty acids, glycerol, steroids & ketone bodies Functions of lipids: 1- serve as an efficient source of energy. 2- serve as a major constituents of the different membranes .such as cell and nuclear membranes

Proteins -3 Carboxyl group Amino group Peptide bond Peptides Essential amino acids Diet Hair Wool Oxygen carriers Muscular contraction Antibodies Cell organelles

‫مجموعة كربوكسيل‬ ‫مجموعة أمين‬ ‫رابطة ببتيدية‬ ‫ببتيدات‬ ‫أحماض أمينية أساسية‬ ‫الطعام‬ ‫شعر‬ ‫صوف‬ ‫حوامل الكسجين مثل الهيموجلوبين‬ ‫النقباض العضلى‬ ‫الجسام المضادة‬ ‫عضيات الخلية‬

Proteins are complex organic nitrogenous substances with high molecular weight. The basic structural units are called amino acids. Each of the 20 amino acids that occur in proteins contains a carboxyl group (-COOH) and an amino group (-NH2) attached to thesame. carbon atom In the molecule of proteins, a carboxyl group of one amino acid is linked to an amino group of another amino acid .forming a peptide bond Peptides containing 2 amino acids are dipeptides, those with 3 amino acids are tripeptides, etc. Those with more than 10 amino acids are .polypeptides

General formula of amino acid

Types of amino acids Non-essential amino acids: -1that can be synthesized in .the cells representing 10 amino acids Essential amino acids:--2that can not be synthesized in the cells representing the other 10 amino acids and so they must be present in the diet (leucine, isoleucine, methionine, phenylalanine, histidine, arginine, lysine, .(tryptophan, valine & threonine Functions of proteins: l- They have a main role in thestructure and function of the cell. 2- Allenzymes are proteins. 3- Serve asstructural elements of the body (e.g. hair, wool, …etc.), others may behormones oroxygen carriers. 4- Participate inmuscular contraction. 5- Participate in the structure ofchromosomes ,antibodies andcell .organelles

Vitamins -4 Small quantities ‫كميات صغيرة‬ Specific metabolic disorders ‫اضطرا بات أيضية معينة‬ Lacking ‫بسبب العوز أو الفقد‬ Symptoms of deficiency Night blindness Retard growth Disorder Rickets Osteomalacia Catabolism Miscarriage

‫أعراض النقص‬ ‫العمى أو العشى الليلى‬ ‫تأخر النمو‬ ‫اضطراب أو اختلل أو اعتلل‬ ‫كساح‬ ‫لين العظام‬ ‫هدم‬ ‫الجهاض أو السقاط‬

‫عقم‬ ‫عوامل التجلط أو التخثر‬ ‫النزيف الزائد‬ ‫تأخر أو تخلف‬ ‫التهاب العصاب‬ ‫الشلل‬ ‫تشقق الجلد‬ ‫الرهاق أو التعب‬ ‫دورة حامض الستريك أو دورة كربس‬ ‫انحلل السكر لمركبات بسيطة‬ ‫السهال‬ ‫التهاب الجلد‬ ‫الضطراب العقلى‬ ‫النيميا نتيجة الخليا الدموية الحمراء العملقة‬ ‫فقر الدم الخبيث‬ ‫تكوين الدم‬ ‫كرة دموية حمراء‪( (RBC‬‬

‫‪Sterility‬‬ ‫‪Clotting factors‬‬ ‫‪Excessive bleeding‬‬ ‫‪Retarded‬‬ ‫‪Neuritis‬‬ ‫‪Paralysis‬‬ ‫‪Skin cracking‬‬ ‫‪Fatigue‬‬ ‫‪Citric acid cycle‬‬ ‫‪Glycolysis‬‬ ‫‪Diarrhea‬‬ ‫‪Dermatitis‬‬ ‫‪Mental disorder‬‬ ‫‪Macrocytic anemia‬‬ ‫‪Pernicious anemia‬‬ ‫‪Hematopoiesis‬‬ ‫‪Erythrocyte‬‬

‫حمض نووى‬ ‫حمض أمينى‬ ‫الكولجين )نوع من البروتين(‬ ‫عظم خرب أو به خلل‬ ‫التئام الجرح‬ ‫عقلى‬ ‫غثيان أو دوار البحر‬

‫‪Nucleic acid‬‬ ‫‪Amino acid‬‬ ‫‪Collagen‬‬ ‫‪Defective bone‬‬ ‫‪Wound healing‬‬ ‫‪Mental‬‬ ‫‪Nausea‬‬

Vitamins are organic compounds needed in small quantities. They can cause specific metabolic disorders when lacking in the diet. :Vitamins are divided into two main groups which are water-soluble vitamins: which include: -1 * Vitamin B complex {thiamine (B1), riboflavin (B2), pantothenic acid (B5), niacin (nicotinic acid), pyridoxine (B6), biotin, cobalamine (B12),folic acid}. * Vitamin C (ascorbic acid). * Vitamin H (biotin)- often considered as a part of vitamin B .complex -2Fat-soluble vitamins: which include: * Vitamin A (retinol). * Vitamin D (cholecalciferol, ergosterol). * Vitamin E (alpha-tocopherol). .(* Vitamin K (phylloquinone

Fat- soluble vitamins Vitamin

Function

Symptoms of deficiency

A

:Necessary for .Rhodopsin synthesis * .Bone & teeth growth * .Normal health of epithelial cells *

.Night blindness * .Retard growth * .Skin disorders *

D

.Promotes Ca & P use * .Bone & teeth formation *

.Rickets * .Osteomalacia *

E

* Prevents catabolism of certain fatty acids. * May prevents miscarriage. * Necessary for synthesis of a number of clotting factors.

* Muscular dystrophy & sterility.

K

* Excessive bleeding due to retarded blood clotting.

Water- soluble vitamins Vitamin

Function

Symptoms of deficiency

B1

Necessary for: * Growth. * Carbohydrate & amino acid metabolism.

* Beriberi. * Muscle weakness. * Neuritis & paralysis.

B2

* Component of FAD (flavin adenine dinucleotide). * Involved in citric acid cycle.

* Eyes disorders. * Skin cracking especially at corners of the mouth.

Pantothenic * Constituent of coenzyme A. acid * Glucose production from lipids & amino acids * Steroid hormone synthesis. * Component of NAD (nicotinamide adenine dinucleotide). B3 * Involved in glycolysis & citric acid cycle.

* Neuromuscular dysfunction & fatigue.

* Pellagra & diarrhea. * Dermatitis & mental disturbance.

(Water- soluble vitamins (continue Vitamin

Function

Symptoms of deficiency

B6

Involved in amino acid * .metabolism

* Dermatitis. * Retard growth.

Folic acid

.Nucleic acid synthesis * .Hematopoiesis *

.Macrocytic anemia *

* Necessary for erythrocyte production. * Some nucleic acid & amino acid metabolism.

* Pernicious anemia. * Nervous system disorders.

B12

(Water- soluble vitamins (continue Vitamin C

Function

Symptoms of deficiency

:Necessary for .Scurvy * .Collagen synthesis * Defective bone * .General protein metabolism * .formation .Poor wound healing *

H Fatty acid & purine * (often considered .synthesis a part of vitamin Movement of pyruvic acid * B complex) .into citric acid cycle

Mental & muscle * .dysfunction .Fatigue & nausea *

Minerals -5 Nutrients Macronutrients Trace elements Poisonous Associated Shares Impulse Transmission Blood clotting Muscle contraction Vital Required

‫مغـﺫيات‬ ‫مغـﺫيات كبيرة‬ ‫عناصر أثرية‬ ‫سام‬ ‫مرافق أو مرتبط‬ ‫يشارك‬ ‫سيال أو نبضة‬ ‫انتقال أو نقل‬ ‫تجلط الدم أو تخثره‬ ‫انقباض العضلة‬ ‫حيوى‬ ‫المطلوب‬

Mineralsare inorganic nutrients which may be: * Macronutrients (needed in relatively large quantities) such as sodium & potassium and * Trace elements (needed in small amounts) such as cobalt, iodine, copper, iron & zinc. .N.B. large amounts of trace elements can be poisonous Sodium (Na -1+): it is found mainly in extracellular fluid associated with chloride & bicarbonate. * It shares in the regulation of acid-base equilibrium. * It shares in the maintenance of osmotic pressure. 2- Potassium (K+): it is found mainly in intracellular fluid * It involves in nerve & muscle impulse transmission. * It is the main constituent of bone & teeth. .* It is required in blood clotting & muscle contraction

Cobalt: * It is a constituent of vitamin B -312. * It is vital for the production of hemoglobin & red blood cells. 4- Iodine: * It is a constituent of thyroxine hormone. 5- Copper: * It is vital for the activation of a variety of enzymes. * It is vital for the production of hemoglobin. 6- Iron: * It is a constituent of hemoglobin & myoglobin. 7- Zinc: * It is an activator of several enzymes. . * It is required for the synthesis of insulin hormone

Digestion Broken down Lumen of digestive tract Anus Digestive juices Gastrointestinal Mastication Grind Small pieces Bolus Reflex of smell, sight Sought of food Initiates Buffering action Moistens and lubricates Swallowed

‫متكسر‬ ‫تجويف القناة الهضمية‬ ‫فتحة الشرج‬ ‫العصارات الهضمية‬ ‫معدى معوى‬ ‫مضغ‬ ‫طحن‬ ‫قطع صغيرة‬ ‫بلبوعة أو بلعة أو مضغة‬ ‫رد فعل للشم والرؤية‬ ‫البحث أو طلب الطعام‬ ‫يبدأ او يستهل‬ ‫تأثير أو فعل منظم‬ ‫يرطب ويزلق أو يزيت‬ ‫يبتلع‬

‫‪Digestion‬‬ ‫يقوى أو يساعد‬ ‫يخرج )من الخراج(‬ ‫ل قنوى أو غدد صماء‬ ‫غدد معدية‬ ‫كلى أو تام‬ ‫التنشيط أو التحفيز العصبى‬ ‫تلمس‬ ‫ينطلق‬ ‫التجبن أو التخثر‬ ‫انسان أو بشر‬ ‫كيموس أو خلصة الطعام المهضوم فى المعدة‬ ‫العضلة العاصرة البوابية‬ ‫المرحلة الرئيسة للهضم‬ ‫الصفراء أو المرارة‬ ‫العصارة البنكرياسية‬ ‫العصارة المعوية‬

‫‪Subserves‬‬ ‫‪Excreted‬‬ ‫‪Endocrine‬‬ ‫‪Gastric glands‬‬ ‫‪Entire‬‬ ‫‪Nervous stimulation‬‬ ‫‪Contact‬‬ ‫‪Releases‬‬ ‫‪Curdling‬‬ ‫‪Human‬‬ ‫‪Chyme‬‬ ‫‪Pyloric sphincter‬‬ ‫‪Major phase of digestion‬‬ ‫‪Bile‬‬ ‫‪Pancreatic juice‬‬ ‫‪Intestinal juice‬‬

‫‪Digestion‬‬ ‫انقباض الحويصلة الصفراوية أو المرارية‬ ‫يفرغ‬ ‫أملح صفراوية‬ ‫اصباغ صفراوية‬ ‫كرة صغيرة أو كرية‬ ‫قطيرات دقيقة‬ ‫تجمع‬ ‫استحلب أو تحول الدهن الى مستحلب دهنى‬ ‫جلسريدات أحادية‬ ‫مـﺫيلت )وحدات حيوية افتراضية(‬

‫‪Contraction of gallbladder‬‬ ‫‪Drains‬‬ ‫‪Bile salts‬‬ ‫‪Bile pigments‬‬ ‫‪Globules‬‬ ‫‪Fine droplets‬‬ ‫‪Aggregating‬‬ ‫‪Emulsification‬‬ ‫‪Monoglycerides‬‬ ‫‪Micelles‬‬

Digestion is a process in which food are broken down into simpler substances that can be absorbed. It takes place in the lumen of digestive tract (alimentary canal). Digestive tract started with mouth, pharynx, oesophagus, stomach, small intestine, large intestine and ended with anus. Food mixed with digestive juices (contain digestive enzymes) which secreted from: 1- glandular tissues that found in the wall of gastrointestinal wall, or 2- glands that lie outside the gastrointestinal tract such as .salivary glands, pancreas and liver Digestion of the major classes of food takes place in the mouth, .stomach and small intestine

Digestion in the mouth -1 It comprises: 1- Mastication: where teeth cut and grind food to small pieces to mix with saliva forming what is known as bolus. 2- Chemical digestion: where salivary amylase (ptyaline) acts on .polysaccharides converting them to the disaccharides maltose Saliva is secreted by 3 pairs of salivary glands (parotid, submaxillary & sublingual). * It is consisted ofwater, organic substances (e.g. amylase & mucin) &inorganic substances (e.g. Cl-1, PO4-3, NaHCO3, Na & K). .* It has a pH between 6.0 & 7.4 The secretion of saliva is continuous and controlled by the autonomic nervous system. Its amount is increased as a result of a reflex of smell, sight or .even the sought of food

Functions of saliva It initiates the digestion of carbohydrates where salivary -1 amylase (ptyaline) acts on polysaccharides converting them into maltose. 2- It has a cleaning action on the mouth & teeth. 3- It protects mouth against acids & alkalies where bicarbonates, phosphates and proteins have an important buffering action. 4- It moistens and lubricates the food to be easily swallowed 5- It dissolves solid foodstuffs due to its high water content and thus subserves the sense of taste. 6- Certain substances such as mercury, lead and iodine salts are .excreted through saliva

Digestion in the stomach -2 The bolus is swallowed to oesophagus then to stomach. The stomach is consisted of fundus, body, antrum and pylorus. The fundus and body are specialized for storage while the .antrum is specialized for mixing food with gastric juice

Also, the antrum is characterized by: * Their gastric glands secrete little acid. .(* Its wall has not endocrine cells that secrete gastrin (hormone

Gastric juice It is secreted from gastric glands which cover almost the entire wall of the stomach. It is formed from water (97%-99%) , mucus, inorganic salts and digestive enzymes (pepsinogen, rennin & lipase). There are different cells that line the wall of gastric gland which are: 1- Parietal (oxyntic) cells which secrete HCl. 2- Chief (peptic) cells which secrete pepsinogen. 3- Mucous cells which secrete mucous. These cells found at the openings of these glands.

The gastric juice is secreted in response to: 1- A nervous stimulation: which is stimulated by the taste, smell, sight of food or thinking of food. 2- A hormonal stimulation: On contact of food with the pyloric mucosa, it releases a hormone called gastrin which passes into the blood and when it returns to the gastric wall it stimulates the gastric cells to produce their secretions. The mechanism of gastric HCl secretion: carbonic anhydrase 1- In parietal cells CO2 (from plasma) + H2O H2CO3 2- H2CO3 HCO3- + H+ 3- HCO3- passes to the plasma in exchange of for Cl- which is coupled to H+ .into the lumen of stomach

Functions of HCl 1- It converts the inactive pepsinogen into active pepsin and provides a suitable medium for its action. 2- It kills most of the bacteria taken in with food. 3- It produces curdling of milk in the stomach which helps to keep it exposed for a longer period to the action of pepsin. 4- When HCl leaves the stomach to duodenum, it stimulates its mucosa to release secretion and pancreozymin hormones which stimulate liver and pancreas to secrete their secretions. Pepsin: (pH 1.8 – 3.5) Pepsinogen (inactive form) Protein

HCl Pepsin

pepsin (active form) Peptones + proteoses

Rennin (milk-curdling enzyme): (pH 5 – 6) Casein (milk protein) (soluble) rennin paracasein (soluble)

++

paracaseinate Ca

(insoluble)

* Paracaseinate is then effected by pepsin. * It is found in the stomachs of young animals but is probably absent in human (pH =5-6).

Gastric lipase: It is of little quantitative importance. At the end of digestion in the stomach the food mass is converted into a liquid called chyme. The chyme passes through the pyloric sphincter to small intestine.

Digestion in the small intestine -3 It is the major phase of digestion. It takes place under the action of 3 juices which arebile, pancreatic juice andintestinal juice. These secretions are regulated by both hormonal (great effect) .and nervous mechanisms When chyme enters the small intestine, HCl, proteoses & peptones stimulates the intestinal mucosa to release 2 hormones which are secretin and cholecystokininpancreozymin (CCK-PZ). Secretin causes the liver, pancreas & small intestine to secrete large quantities of fluid rich in bicarbonate. CCK-PZ causes : * Contraction of gallbladder to release bile. * Release of enzyme-rich pancreatic and intestinal juices.

1- Bile It is continually secreted by liver cells which passes through bile duct which drains into the duodenum. Between meals bile stored in gallbladder. It is greenish alkaline fluid containing water, inorganic salts (mainly bicarbonate) & organic salts (bile salts and bile pigments). N.B. There is enzymes in the bile. Bicarbonate aids in the neutralization of acid chyme which enters the duodenum. Functions of bile salts: 1- Activate pancreatic lipase. 2- Increase the rate of fat digestion and absorption in two ways: a- Break large fat globules up into fine droplets & prevent them from aggregating into larger ones. This process is called emulsification. B- Combine with fatty acids and monoglycerides to form small, water-soluble aggregations known as micelles.

2- Pancreatic juice It is alkaline watery fluid containing inorganic salts (mainly bicarbonate) & organic salts (enzymes for digesting all 3 major types of food: carbohydrates, proteins & lipids). Bicarbonate aids in the neutralization of acid chyme.

A- Amylolytic enzymes: i.e. digestion of carbohydrates. Pancreatic amylase

Starch, glycogen & most carbohydrates

Disaccharides

B- Proteolytic enzymes: i.e. digestion of proteins. It comprises trypsinogen, chymotrypsinogen & procarboxypolypeptidase which are inactive forms.

Trypsinogen

Enterokinase

Trypsin

(secreted by intestinal mucosa)

Autocatalysis

Chymotrypsinogen

Trypsin

Procarboxypolypeptidase

Trypsin

Proteoses + Peptones Carboxypolypeptides

Chymotrypsin Carboxyplypeptidase

Trypsin & Chymotrypsin Carboxypolypeptidase

Polypeptides Amino acids

C- Lipolytic enzymes: i.e. digestion of lipids. Emulsified fat

Pancreatic lipase

Fatty acid + monoglycerides

3- Intestinal juice It is secreted by the tubular glands of the intestine. It is an alkaline fluid containing water, minerals & digestive enzymes which are amylolytic & proteolytic.

A- Amylolytic enzymes: such as disaccharidases e.g. maltase, sucrase & lactase.. Maltose

Maltase

Glucose + Glucose

Sucrose

Sucrase

Glucose + Fructose

Lactose

Lactase

Glucose + Galactose

B- Proteolytic enzymes: such as aminopolypeptidase, dipeptidase & enterokinase.. Aminopolypeptides Dipeptides Trypsinogen

Aminopolypeptidase dipeptidase Enterokinase

Amino acids Amino acids Trypsin

‫الى‬ ‫اللقــــــــــــــــــ‬ ‫ـاء‬ ‫أ‪ .‬د‪ .‬شــــــبل‬ ‫شـــــــــعلن‬