front 1 What are body planes? | back 1 Imaginary lines used for reference. |
front 2 What are the different planes in the human body used? | back 2 Median plane, coronal plane, and transverse plane. |
front 3 What is a section? | back 3 A real or an imaginary cut made along a plane. |
front 4 What is a cut along the median plane? | back 4 Sagittal section. |
front 5 What is a cut along the coronal plane? | back 5 Frontal section. |
front 6 What is a cut through the transverse plane? | back 6 Cross-section. |
front 7 What is anatomical position? | back 7 The body is erect, feet are slightly apart, the head is held high, and the palms of the hands are facing forward. |
front 8 What are the directional terms? | back 8 Superior, inferior, anterior, posterior, medial, lateral, proximal, and distal. |
front 9 What is the dorsal cavity? | back 9 Includes the cranial and spinal cavities. |
front 10 What is the ventral cavity? | back 10 Includes the orbits and the nasal, oral, thoracic, and abdominalpelvic cavities. |
front 11 What is Histology? | back 11 The study of tissues. |
front 12 What is a tissue? | back 12 A group of cells that act together to perform a specific function. |
front 13 What are the four fundamental tissues? | back 13 Epithelial, connective, muscle, and nerve tissue. |
front 14 What is Epithelial tissue? | back 14 Cells over, line and protect the body and it's internal organs. |
front 15 What is Connective tissue? | back 15 Framework of the body, providing support and structure for the organs. |
front 16 What is Nerve tissue? | back 16 Composed of neurons and connective tissue cells that are referred to as neuroglia. |
front 17 What is Muscle tissue? | back 17 Tissue that has the ability to contract or shorten. Voluntary muscle (skeletal) and involuntary muscle (smooth muscle and cardiac muscle). |
front 18 What is a cell? | back 18 The basic unit of life and the building block of tissues and organs. |
front 19 What is an organelle? | back 19 A object inside a cell that has a specific function. |
front 20 What is a nucleus? | back 20 Contains deoxyribonucleic acid (DNA). Main part of a Eukaryotic cell. |
front 21 What is a Ribosome? | back 21 Used for synthesis of proteins. |
front 22 What are enzymes? | back 22 Proteins (99%), that regulate all chemical reactions in the body. |
front 23 What is Mitosis necessary for? | back 23 Growth and repair. |
front 24 What happens during Mitosis? | back 24 The DNA is duplicated and distributed evenly to two daughter cells. |
front 25 What is Meiosis? | back 25 Special cell division that takes place in the gonads (ovaries and testes), the chromosome number is reduced from 46 to 23, so when the egg and sperm unite in fertilization the zygote will have the correct number of chromosomes. |
front 26 What are the principal membranes? | back 26 Mucous, serous, synovial, and cutaneous - composed of epithelial tissue. |
front 27 What are the different types of glands? | back 27 Sudoriferous, sebaceous, and ceruminous. |
front 28 Where does cartilage replace bone in embryonic development? | back 28 Joints, the thorax, and various rigid tubes. |
front 29 What is the largest organ in the body? | back 29 The skin. |
front 30 What does the skin consist of? | back 30 Two layers: the epidermis (the outer most protective layer of dead keratinized epithelial cells; and the dermis which is the underlying layer of connective tissue with blood vessels, nerve endings, and the associated skin structures. |
front 31 What does the Dermis rest on? | back 31 The subcutaneous tissue that connects the skin to the superficial muscles. |
front 32 What are the layers of the Epidermis? | back 32 Stratum corneum, stratum lucedum, tratum granulosum, and the inner most stratum germinativum. |
front 33 What layer does mitosis occur in the Epidermis? | back 33 The stratum gerninativum. |
front 34 What is Melanin? | back 34 A protein pigment found in epidermal cells, protect skin against radiation from the sun. |
front 35 What does the Dermis contain? | back 35 Fibrous connective tissue with blood vessels, sensory nerve endings, hair follicles, and glands. |
front 36 What are the two types of sweat glands? | back 36 Eccrine and apocrine. |
front 37 What are Eccrine glands? | back 37 Widely most distrubuted sweat glands that regulate the body tempearture by releasing a watery scretion that evaporates from the surface of the skin. |
front 38 What are Apocrine glands? | back 38 Mainly in the armpits and the groin area. Contains bit of cytoplasm from the secreting cells. The cell debris attracts bacteria, and the presense of bacteria results in body oder. |
front 39 What do Sebaceous glands release? | back 39 Sebum - through the hair follicles that lubricates the skin and prevents drying. |
front 40 What is oil produced by? | back 40 Holocrine secretion, in which whole cells of the gland are part of the secretion. |
front 41 What are the appendages of the skin? | back 41 Hair and nails. |
front 42 What are hair and nails composed of? | back 42 A strong protein called keratin. |
front 43 What can hair, skin and nails be used for in diagnosis? | back 43 They may show changes in different diseases that can be used in clincal conditions. i.e., skin cancer is a clinical condition that is associated with the skin. |
front 44 What does the bodys framework consist of? | back 44 Bone, cartilage, ligaments, plus the joints between the bones. |
front 45 What are the functions of the skeletal system? | back 45 Support, permission of movement, blood cell formation (hemopoiesis), protection of internal organs, detoxification (removal of poisons), provision for muscle attachment, and mineral storage (particularly calcium and phosphorus). |
front 46 What are the different shapes of bones? | back 46 Long, short, flat, irregular, and sesamoid. |
front 47 What is a Long bone? | back 47 Has an iregular epiphysis at each end, composed mainly of spongy (cancellous) bone, and a shaft or diaphysis, composed mainly of compact bone. |
front 48 What are the cells that form compact bone? | back 48 Osteoblasts. |
front 49 What do Osteoblasts turn into when they become fixed in the dense bone matrix? | back 49 They stop dividng but continue to maintain bone tissue as osteocytes. |
front 50 What does the axial skeleton consist of? | back 50 28 bones of the skull. Separated into 14 facial bones, and the 14 bones of teh cranium.; and 33 bones of the veretebral column. Final portion consist of the bones of the thorax, the sternum and the 12 pairs of ribs. |
front 51 What are the facial bones? | back 51 Two nasal bones, two maxillary bones, two zygomatic bones, one mandible (only moveable bone in the skull), two palatine bones, one vomer, two lacrimal bones, and two inferior nasal conchae. |
front 52 What do the bones of the cranium consist of? | back 52 Single occipital, frontal, ehtmoid, and sphenoid and the paired parietal, temporal, and ossicles of the ear. |
front 53 What are the ossicles of the ear? | back 53 Malleus, incus and stapes. |
front 54 What are the bones of the vertebral column? | back 54 Seven cervical vertebrae, 12 thoracic vertebrae, five lumbar vertebrae, five sacral vertebrae (fused to form the sacrum), and the occygeal vertebrae (tailbone. |
front 55 What does the Appendicular Skeleton consist of? | back 55 Includes the bones of girdles and the limbs. |
front 56 What is the upper portion of the appendicular skeleton? | back 56 Consists of the pectoral or shoulder girdle, the clavicle and scapula and the upper extremeity. |
front 57 What are the bones in the arm? | back 57 The humerus, the radius and ulna, the carpals (wrist bones), the metatarsals (bones of the hand), and the phalanges (bones of the fingers). |
front 58 What is the lower portion of the appendicular skeleton? | back 58 Consists of the pelvic girdle or os coxae, and the lower extremitys. |
front 59 What does the os Coxae consist of? | back 59 Consists of the fused ilium, ischium and pubis. |
front 60 What do the lower extremeitys of the appendicular skeleton consist of? | back 60 Femur (thighbone), the tibia and fibula, the tarsals (ankle bones), the metatarsals (bones of the foot), and the phalanges. |
front 61 How do Muscles produce movement? | back 61 By contracting in response to nervous stimulation. |
front 62 What does Muscle contraction result from? | back 62 Sliding together of actin and myosin filaments within the muscle cell or fiber. |
front 63 What does each muscle cell consist of? | back 63 Myofibrils, which in turn are made up of still smaller units called sarcomeres. |
front 64 What needs to happen for a muscle cell to contract? | back 64 Calcium and ATP (adenosine triphosphate) must be present. Nervous stimulation from motor neurons cause the release of calcium ions from the sacroplasmic reticulum. Calcium ions attach to inhibitory proteins on the actin filaments within the cell, moving them aside so that cross-bridges can form between actin and myosin filamens. Using energy supplied by ATP, the filaments slide together to produce contraction. |
front 65 What are Skeletal muscles? | back 65 Make up the muscular system, also called voluntary muscle because they are under concious control. These muscles must work in pairs. |
front 66 What is a prime mover? | back 66 A muscle that executes a given movement. |
front 67 What is the Antagonist? | back 67 A muscle that provides the opposite movement. |
front 68 What are synergists? | back 68 Muscles that may work in cooperation with the prime mover. |
front 69 How can muscles be classified? | back 69 According to the movement they elicit. There are flexors and extensors. Abducters and adducters. |
front 70 What is a flexor? | back 70 Reduce the angle at the joint. |
front 71 What is an extensor? | back 71 Increase the angle at the joint. |
front 72 What is an abductor? | back 72 Draw the limb away from the midline. |
front 73 What is an adductor? | back 73 Return the limb back toward the body. |
front 74 What does the Nervous System consist of? | back 74 Brain, spinal cord, and the nerves. |
front 75 What is the function of the Nervous System? | back 75 This vital system enables us to percieve many of the changes that take place in our external and internal environments and to respond to those changes (seeing, hearing, tasting, smelling and touching are examples of perception). It enables us to think, reason, remember and carry out other abstract activities. It makes possible body movements by skeletal muscles, by supplying them with nerve impulses that cause contraction. It works closely with endocrine glands, correlating and integrating body functions such as digestion and reprodution. |
front 76 What do all actions of the nervous system depend on? | back 76 The transmission of nerve impulses over neurons or nerve cells. |
front 77 What are Nerve cells? | back 77 The functional units of the nervous system. |
front 78 What are the main parts of a Neuron? | back 78 Body, axon and dendrites. |
front 79 What are dendrites? | back 79 Trasmit the impulse toward the cell body. |
front 80 What are axons? | back 80 Transmit the impulse away from the body. |
front 81 How is the Nervous System divided? | back 81 Central Nervous System (CNS), and the Peripheral Nervous System (PNS). |
front 82 What does the PNS consist of? | back 82 All the nerves that transmit information to and from the CNS. |
front 83 What do Sensory (Afferent) neurons trasmit? | back 83 Trasmit nerve impulses toward the CNS. |
front 84 What do Motor (Efferent) neurons transmit? | back 84 Transmit nerve impulses away from the CNS, toward the effector organs such as the muscles, glands, and digestive organs. |
front 85 What are the major parts of the brain? | back 85 The cerebrum (associated with movement and sensory input), the cerebellum (responsible for muscular coordiation), and the medulla oblongata (controls many vital functions such as respiration and heart rate). |
front 86 What is the Spinal Cord? | back 86 Approximately 18 inches long and extends from the base of the skull (foramen magnum) to the first or second lumbar veretebra (L1 or L2). |
front 87 How many pairs of spinal nerves exit the spinal cord? | back 87 Thirty-one. |
front 88 What are Simple Spinal Reflexes? | back 88 Relfexes in which nerve impulses travel through the spinal cord only and do not reach the brain. |
front 89 What are the different tracts to and from the brain of the Spinal Cord? | back 89 Ascending and descending tracts. |
front 90 Where do Sensory impulses enter? | back 90 The dorsal horns of the spinal cord. |
front 91 Where do Motor impulses leave? | back 91 The ventral horns of the spinal cord? |
front 92 What is the Endocrine system? | back 92 Assists the nervous system in homeostasis and plays important roles in growth and sexual maturation. |
front 93 Where do the Endocrine System and the Nervous system meet? | back 93 The hypothalamus and the pituitary gland. |
front 94 What governs the Pituitary Gland? | back 94 The hypothalamus. |
front 95 What is the Hypothalamus controlled by? | back 95 The feedback of hormones in the blood? |
front 96 What is the difference between the control of the Central Nervous System and the Endocrine System? | back 96 The endocrine system has long-lasting and widespread effects. |
front 97 What are Hormones? | back 97 Chemical messengers that control the growth, differentiation, and metabolism of specific target cells. |
front 98 What are the two major groups of hormones? | back 98 Steroid hormones, and protein hormones. |
front 99 What are Steriod hormones? | back 99 Hormones that target the cells and have direct effect on the DNA of the nucleus. |
front 100 What are Protein hormones? | back 100 Hormones that remain at the cell surface and act through a second messenger; usually adenosine mono phosphate (AMP). |
front 101 How do most hormones affect cell activity? | back 101 By altering the rate of protein synthesis. |
front 102 What is the pituitary gland? | back 102 The master gland, it is attached to the hypothalamus by a stalk called the infundibulum. It has two major portions: the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis). |
front 103 What are the hormones of the adenohypophysis called? | back 103 Tropic hormones because they act mainly on other endocrine glands. i.e.; Somatotropin (STH) or growth hormone (GH), adenocorticotropic hormone (ACTH), Thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH). |
front 104 What do hormones released from the posterior lobe of the pituitary consist of? | back 104 Oxytocin (the labor hormone) and antidiuretic hormone (ADH). |
front 105 What are the other important endocrine glands? | back 105 Thyroid, parathyroid, adrenals, pancreas and the gonads (the ovaries and the testes). |
front 106 What does whole blood consist of? | back 106 55% plasma and 45 % formed elements. |
front 107 What are formed elements? | back 107 Erythrocytes (Red Blood Cells), Leukocytes (White Blood Cells), and platelets. |
front 108 Where are formed elements produced? | back 108 Produced from stem cells in red bone marrow. |
front 109 What are Erythrocytes? | back 109 Modified formed elements that are used for transport of oxygen. |
front 110 What is oxygen bounded too? | back 110 Bounded to the pigmented protein hemoglobin. |
front 111 How are the five types of leukocytes distinguished? | back 111 Basis of size, appearance of the nucleus, staining properties, and presense or absense of visible cytoplasmic granules. |
front 112 What are WBC's active in? | back 112 Phagocytosis (neutrophils and monocytes), and antibody formation (lymphcytes). |
front 113 What is the purpose of platelets? | back 113 Active in the process of blood clotting. |
front 114 What does Blood serve for? | back 114 Transportation of oxygen and nutrients to body cells and to carry away carbon dixoide and metabolic waste. |
front 115 What does Plasma contain? | back 115 Approximately 10% proteins, ions, nutrients, waste products and hormones, which are dissolved or suspended in water. |
front 116 What is the heart? | back 116 A double pump that sends blood to the lungs for oxygenation through the pulmonary circuit and to the remainder of the body through the systemic circult. |
front 117 Where is blood recieved? | back 117 The atria. |
front 118 Where is blood pumped into circulation by? | back 118 The ventricles. |
front 119 What are the valves between the atria and the ventricles? | back 119 Include the tricuspid on the right side of the heart and the bicuspid on the left. |
front 120 What are Semilunar valves? | back 120 Found at the entrances of the pulmonary trunk and the aorta. |
front 121 How is blood supplosed to the heart muscle (the myocardium)? | back 121 Through the coronary arterties. |
front 122 Where does Blood drains from the myocardium directly into? | back 122 Right atrium through the coronary sinus. |
front 123 What is the hearts intrinsic beat initiated by? | back 123 The sinoatrial node and transmitted along a conduction system through the myocardium. |
front 124 What does the ECG measure? | back 124 The wave of electrical activity of the intrinsic beat that in initiated by the sinoatrial node and transmitted along a conuction system through the myocardium. |
front 125 What is the cardiac cycle? | back 125 The period from the end of one ventricular contraction to the end of the next ventricular contraction. |
front 126 What is the contraction phase of the cardiac cycle? | back 126 Systole. |
front 127 What is the relaxation phase of the cardiac cycle? | back 127 Diastole. |
front 128 What does the Vascular system include? | back 128 Arteries that carry blood away from the heart, veins that carry blood toward the heart, and the microscopic vessesl (the capillaries) through which exchanges take place betwen the blood and the cells of the body. |
front 129 Where do the systemic arteries begin? | back 129 The aorta, which sends branches to all parts of the body. |
front 130 What happens to arteries as they get farther away from the heart? | back 130 They become thinner and thinner. |
front 131 What are the smallest arteries called? | back 131 Arterioles. |
front 132 What is the Superior and Inferior Vena Cavae? | back 132 Large veins that empty into the right atrium of the heart. |
front 133 What is the structure of artery walls? | back 133 Thick and elastic. They carry blood under high pressure. |
front 134 What do Vasoconstriction and vasodilation result from? | back 134 Contraction and relaxation of smooth muscle in the arterial walls. |
front 135 What do Vasoconstriction and vasodilation influence? | back 135 Blood pressure and blood distribution to the tissues. |
front 136 What is the structure of veins walls? | back 136 Thinner and less elastic then those of the arteries, they carry blood under lower pressure. |
front 137 What are Mechanisms that draw venous blood back to the heart? | back 137 Pressure of skeletal muscle on the veines, expansion of the chest in breathing, and valves in the veins of the legs that keep blood moving in a forward direction. |
front 138 What are the components of the Respiratory System? | back 138 The nose, phayrnx, larynx, trachae, bronchi, lungs with their alveoli, diaphragm and muscles surrounding the ribs. |
front 139 What is Respiration controllded by? | back 139 The respiratory control center in the medulla of the brain. |
front 140 What does the Respiratory System do? | back 140 Oxygen to the body and elimantes carbon dioxide. |
front 141 What is External Respiration? | back 141 Refers to the exchange of gases between the atmosphere and the blood through the alveoli. |
front 142 What is Internal Respiration? | back 142 Refers to the exchange of gases between the blood and the body cells. |
front 143 What do the passageways between the nasal cavity and the alveoli serve as? | back 143 Conduction of gases to and from the lungs. Also to warm, filter, and moisten upcoming air. |
front 144 What are the upper respiratory tubules lined with? | back 144 Cilia that help to trap debris and keep foreign substances from entering the lungs. |
front 145 What does Inhalation require? | back 145 Contraction of the diaphragm to enlarge the chest cavity and draw air into the lungs. |
front 146 What is Exhalation? | back 146 A passive process during which the lungs recoil as the respiratory muscles relax and the horax decreases in size. |
front 147 When is oxygen released from hemoglobin? | back 147 When the concentration of oxygen drops in the tissues. |
front 148 What is carbon dioxide converted to? | back 148 Bicarbonate ion by carbonic anhydrase within red blood cells. This also release hydrogen ions, Co2 remains as a regulator of blood pH. |
front 149 What does the ailentary canal consist of? | back 149 The mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus. |
front 150 What are the accessory organs of digestion? | back 150 The liver, pancreas, and gallbladder. |
front 151 What happens to food in the mouth? | back 151 It is ingested in the mouth, where it is mechanically broken down by the teeth and tongue in the process of mastication (chewing). |
front 152 What is Saliva produced by? | back 152 The three pairs of salivary glands, which lubricates and dilutes the chewed food. |
front 153 What does Saliva contain? | back 153 An enzyme called amylase that starts the digestion of complex carbohydrates. |
front 154 What is a bolus? | back 154 A ball of food that is formed. |
front 155 What do the constrictive muscles of the pharynx do? | back 155 Force the food into the upper portion of the esophagus, and the food is swallowed. |
front 156 What is the esophagus? | back 156 A narrow tube leading from the pharynx to the stomach. |
front 157 What are the four main layers of the digestive tract? | back 157 The mucous membrane, the submucous layer, the muscular layer and the serous layer. |
front 158 What happens when food enters the stomach? | back 158 Gastric glands secrete hydrochloric acid that breaks down food. The stomach muscle churns and mixes the bolus of food, turning the mass into a soupy substance. |
front 159 What is the soupy substance that the stomace muscle turns the bolus into? | back 159 Chyme. |
front 160 Where does most digestion and absorption of food occur? | back 160 The small intestine. |
front 161 What happens to food in the small intestine? | back 161 It is acted on by various enzymes from the small intestine and pancreas, and by bile from the liver. |
front 162 What does the pancreas contribute? | back 162 Water to dilute the chyme and bicarbonate ions to neutralize the acid from the stomach. |
front 163 What does the small intestine consist of? | back 163 Three major regions: the duodenum, the jejunum, and the ileum. |
front 164 What does the small intestine absorb? | back 164 Nutrients, amino acids and simple sugars derived from proteins and carbohydrates directly into the blood. |
front 165 Where is fat absorbed? | back 165 Into the lymph by the lacteals, which eventually are added to the bloodstream. |
front 166 What happens to all the nutrients after they are absorbed into the blood? | back 166 They enter the hepatic portan vein to be routed to the liver for decontamination. |
front 167 What are Villi? | back 167 Small fingerlike projections that greatly increase the surface area of the intestinal wall. |
front 168 What does the large intestine do? | back 168 Reabsorbs water and stores and eliminates undigested food. |
front 169 What can be found in the large intestine? | back 169 Abdundant bacteria and intestinal flora. |
front 170 What is the large intestine arranged into? | back 170 Five portions: the ascending colon, the transverse colon, the descending colon, the sigmoid colon and the rectum. |
front 171 What is the anus? | back 171 The opening for defecation (expelling of stool). |
front 172 What is the urinary system? | back 172 Consisting of two kidneys, two ureters, a urinary bladder, and the urethra. |
front 173 What do the kidneys do? | back 173 Filter the blood. |
front 174 What do ureters do? | back 174 Transport urine to the urinary bladder, where urine is stored before urination through the urethra to the outside. |
front 175 What are the functional units of the kidney? | back 175 Nephrons - small coiled tubes filter waste material out of blood brought to the kidneys by the renal artery. |
front 176 Where does the actual filteration process occur in the Nephron? | back 176 Through the glomerulus in the Bowman's capsule of the nephron under the force of blood pressure. |
front 177 What happens as the glomerular filtrate passes through the nephron? | back 177 Components needed by the body such as water, glucose, and ions leave the nephron by diffusion and reenter the blood. |
front 178 Where is water reabsorbed in the nephron? | back 178 The tubules of the nephron. |
front 179 What is the final product of the Nephrons per kidney? | back 179 Urine. |
front 180 What are the male and female sex organs? | back 180 The testes and the ovaries. |
front 181 What are the functions of the sex organs? | back 181 Production of gametes (sex cells) and production of hormones. Under the c ontrol of tropic hormones from the pituitary gland. |
front 182 What is the reproductive activity in women? | back 182 Cyclic. |
front 183 What is the reproductive activity in men? | back 183 Continuous. |
front 184 How are gametes formed? | back 184 Meiosis. |
front 185 Where do spermatozoa develop? | back 185 The semineiferous tubules of each testis. |
front 186 Where is testosterone produced? | back 186 Interstitial cells between the seminiferous tubules. |
front 187 What does testosterone do? | back 187 Influences sperm cell development and also produces the male secondary sex characteristics such as body hair and deep voice. |
front 188 Where is sperm stored once produced? | back 188 Epididymis of each testis. |
front 189 What is the pathway for sperm during ejaculation? | back 189 Vas deferens, ejaculatory duct, and urethra. |
front 190 What are the glands that produce the transport medium semen? | back 190 Seminal vesicles, p orstate gland, and bulbourethral (Cowper's) glands. |
front 191 What is testicular control under? | back 191 Two anterior pituitary hormones - FSH which stimulates sperm production and - ICSH Interstital cell stimulating hormone or LH that stimulates the intersitial cells to produce testosterone. |
front 192 What happens in women each month? | back 192 Under the influence of FSH, several eggs ripen within the ovarian follicles in the ovary. |
front 193 What initiates the preparation of the endometrium of the uterus for pregnancy? | back 193 Estrogen produced by the follicle. |
front 194 What happens at day 14 of the cycle in women? | back 194 LH is released from the pituitary, which stimulates ovulation and the conversion of the follicle of the corpus luteum. |
front 195 What does the Corpus Luteum secrete? | back 195 The hormone progesterone, which further stimulates development of the endometrium. |
front 196 What happens if Fertilization occurs in a woman? | back 196 The corpus luteum remains function. |
front 197 What happens if Fertilization doesnt occur in a woman? | back 197 The corpus luteum degenerates and menstruation begins. |
front 198 What happens to the egg after ovulation? | back 198 The egg is swept into the oviduct or fallopian tube. |
front 199 What happens if fertilization occurs in the oviduct or fallopian tube? | back 199 The fertilized egg or zygote travels to the uterus and implants itself within the endometrium. |
front 200 What nourishes the developing embryo in the uterus? | back 200 The placenta which is fomred by materal and embryonic tissue. |
front 201 What happens during pregnancy? | back 201 Hormones from the placenta maintain the endometrium and prepare the breasts for milk production. |