Skull of mammals is

\( \newcommand\) • • • • Mammalian traits include, among others: specialized glands, modified jaw and inner ear bones, urinary bladder, and hair. Key Points • The various traits which are used to define mammals include: the presence of hair; the integument system which contains specialized secretory glands; the skeletal and muscular systems; the heart and brain structure. • Mammals contain specialized glands which have various functions: secretion of chemical compounds used for communication; glands that produce milk; glands that produce perspiration used for thermoregulation; and glands that produce sebum, which is used for lubrication. • Mammals have four-chambered hearts that are defined by the ability to regulate the heart beat with the presence of specialized pacemaker cells. • A mammal’s hair has many purposes, including insulation, sensory perception, protective coloration, and social signaling. • Mammals possess many unique skeletal structures including a single lower jaw bone that joins the skull at the squamosal bone and three bones in the inner ear. Key Terms • vibrissa: any of the tactile whiskers on the nose of an animal • sebum: a thick oily substance, secreted by the sebaceous glands of the skin, that consists of fat, keratin and cellular debris • diphyodont: having two successive sets of teeth (deciduous and permanent), one succeeding the other • sinoatrial node: the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus th...

[ "article:topic", "authorname:openstax", "apocrine gland", "dentary", "diphyodont", "eccrine gland", "eutherian mammal", "heterodont tooth", "mammal", "mammary gland", "marsupial", "monotreme", "Ornithorhynchidae", "sebaceous gland", "Tachyglossidae", "showtoc:no", "license:ccby", "licenseversion:40", "program:openstax" ] Skills to Develop • Name and describe the distinguishing features of the three main groups of mammals • Describe the proposed line of descent that produced mammals • List some derived features that may have arisen in response to mammals’ need for constant, high-level metabolism Mammals are vertebrates that possess hair and mammary glands. Several other characteristics are distinctive to mammals, including certain features of the jaw, skeleton, integument, and internal anatomy. Modern mammals belong to three clades: monotremes, marsupials, and eutherians (or placental mammals). Characteristics of Mammals The presence of hair is one of the most obvious signs of a mammal. Although it is not very extensive on certain species, such as whales, hair has many important functions for mammals. Mammals are endothermic, and hair provides insulation to retain heat generated by metabolic work. Hair traps a layer of air close to the body, retaining heat. Along with insulation, hair can serve as a sensory mechanism via specialized hairs called vibrissae, better known as whiskers. These attach to nerves that transmit information about sensation, which is particularly use...

Contents • 1 Objectives • 2 The Vertebral Column • 3 The Skull • 4 The Rib • 5 The Forelimb • 6 The Hind Limb • 7 The Girdles • 8 Categories Of Bones • 9 Bird Skeletons • 10 The Structure Of Long Bones • 11 Compact Bone • 12 Spongy Bone • 13 Bone Growth • 14 Broken Bones • 15 Joints • 16 Common Names Of Joints • 17 Locomotion • 18 Summary • 19 Worksheet • 20 Test Yourself • 21 Websites • 22 Glossary Objectives [ | ] After completing this section, you should know: • the functions of the skeleton • the basic structure of a vertebrae and the regions of the vertebral column • the general structure of the skull • the difference between ‘true ribs’ and ‘floating ribs • the main bones of the fore and hind limbs, and their girdles and be able to identify them in a live cat, dog, or rabbit Fish, frogs, reptiles, birds and mammals are called vertebrates, a name that comes from the bony column of vertebrae (the spine) that supports the body and head. The rest of the skeleton of all these animals (except the fish) also has the same basic design with a skull that houses and protects the brain and sense organs and ribs that protect the heart and lungs and, in mammals, make breathing possible. Each of the four limbs is made to the same basic pattern. It is joined to the spine by means of a flat, broad bone called a girdle and consists of one long upper bone, two long lower bones, several smaller bones in the wrist or ankle and five digits (see diagrams 6.1 18,19 and 20). Diagram 6.1 - Th...

Contents • 1 Objectives • 2 The Vertebral Column • 3 The Skull • 4 The Rib • 5 The Forelimb • 6 The Hind Limb • 7 The Girdles • 8 Categories Of Bones • 9 Bird Skeletons • 10 The Structure Of Long Bones • 11 Compact Bone • 12 Spongy Bone • 13 Bone Growth • 14 Broken Bones • 15 Joints • 16 Common Names Of Joints • 17 Locomotion • 18 Summary • 19 Worksheet • 20 Test Yourself • 21 Websites • 22 Glossary Objectives [ | ] After completing this section, you should know: • the functions of the skeleton • the basic structure of a vertebrae and the regions of the vertebral column • the general structure of the skull • the difference between ‘true ribs’ and ‘floating ribs • the main bones of the fore and hind limbs, and their girdles and be able to identify them in a live cat, dog, or rabbit Fish, frogs, reptiles, birds and mammals are called vertebrates, a name that comes from the bony column of vertebrae (the spine) that supports the body and head. The rest of the skeleton of all these animals (except the fish) also has the same basic design with a skull that houses and protects the brain and sense organs and ribs that protect the heart and lungs and, in mammals, make breathing possible. Each of the four limbs is made to the same basic pattern. It is joined to the spine by means of a flat, broad bone called a girdle and consists of one long upper bone, two long lower bones, several smaller bones in the wrist or ankle and five digits (see diagrams 6.1 18,19 and 20). Diagram 6.1 - Th...

[ "article:topic", "authorname:openstax", "apocrine gland", "dentary", "diphyodont", "eccrine gland", "eutherian mammal", "heterodont tooth", "mammal", "mammary gland", "marsupial", "monotreme", "Ornithorhynchidae", "sebaceous gland", "Tachyglossidae", "showtoc:no", "license:ccby", "licenseversion:40", "program:openstax" ] Skills to Develop • Name and describe the distinguishing features of the three main groups of mammals • Describe the proposed line of descent that produced mammals • List some derived features that may have arisen in response to mammals’ need for constant, high-level metabolism Mammals are vertebrates that possess hair and mammary glands. Several other characteristics are distinctive to mammals, including certain features of the jaw, skeleton, integument, and internal anatomy. Modern mammals belong to three clades: monotremes, marsupials, and eutherians (or placental mammals). Characteristics of Mammals The presence of hair is one of the most obvious signs of a mammal. Although it is not very extensive on certain species, such as whales, hair has many important functions for mammals. Mammals are endothermic, and hair provides insulation to retain heat generated by metabolic work. Hair traps a layer of air close to the body, retaining heat. Along with insulation, hair can serve as a sensory mechanism via specialized hairs called vibrissae, better known as whiskers. These attach to nerves that transmit information about sensation, which is particularly use...

\( \newcommand\) • • • • Mammalian traits include, among others: specialized glands, modified jaw and inner ear bones, urinary bladder, and hair. Key Points • The various traits which are used to define mammals include: the presence of hair; the integument system which contains specialized secretory glands; the skeletal and muscular systems; the heart and brain structure. • Mammals contain specialized glands which have various functions: secretion of chemical compounds used for communication; glands that produce milk; glands that produce perspiration used for thermoregulation; and glands that produce sebum, which is used for lubrication. • Mammals have four-chambered hearts that are defined by the ability to regulate the heart beat with the presence of specialized pacemaker cells. • A mammal’s hair has many purposes, including insulation, sensory perception, protective coloration, and social signaling. • Mammals possess many unique skeletal structures including a single lower jaw bone that joins the skull at the squamosal bone and three bones in the inner ear. Key Terms • vibrissa: any of the tactile whiskers on the nose of an animal • sebum: a thick oily substance, secreted by the sebaceous glands of the skin, that consists of fat, keratin and cellular debris • diphyodont: having two successive sets of teeth (deciduous and permanent), one succeeding the other • sinoatrial node: the impulse-generating (pacemaker) tissue located in the right atrium of the heart, and thus th...