Aging and Senescence
Aging and Senescence Lifespans, even of closely related species (e.g. mammals), can be very varied: for example a hamster 3 years, a human 80 years. Changes associated with age are …
Aging and Senescence Lifespans, even of closely related species (e.g. mammals), can be very varied: for example a hamster 3 years, a human 80 years. Changes associated with age are …
Puberty In Humans ▶Puberty onset Puberty is a period of rapid body growth and development. accompanied by the secretion of gonadal hormones and the development of sexual maturity, including the …
The Menstrual Cycle In Women ▶Pre-ovulation After puberty in women, the menstrual (monthly) cycle is established. The production of eggs (oocytes) is cyclical: it involves an interplay of hormones and …
Mid-Life And Menopause In Humans ▶Mid-life Mid-life spans the years between puberty and old age (senescence). In men, maximum secretion of testosterone occurs between 18 and 20 years of age; …
Cytoskeleton Most cells contain cytoskeletal elements comprising contractile filaments of actin and myosin, together with microtubules. This permits shape changes in the cells and facilitates the evolution of specialized mechanisms …
Veins of the Neck The veins of the neck include the external jugular, internal jugular, vertebral, and subclavian veins External Jugular Vein The external jugular vein is formed by the …
Nose (Nasal Cavity) The median nasal septum, consisting of bony and cartilaginous components, subdivides the nasal cavity into a right and a left nasal fossa, Each nasal fossa has anterior …
Anatomy of Tongue The tongue, a muscular organ, is divided for descriptive purposes into the body, which lies relatively free in the oral cavity, and the base, which is fixed …
Bone And Connective Tissue In The Vertebrate Skeleton Connective tissue Connective tissue is abundant in the body: it is characterized by few cells, extensive intercellular mineral and/or protein, and a …
Class Reptilia- Turtles The reptiles constitute one of the most interesting, and, in general, one of the least known classes of the vertebrates. They are cold-blooded; usually covered with scales, …
Animal Hormones Vertebrate Endocrine Glands and Hormones Hormones and Nerves Increasing size and complexity in multicellular animals necessitates communication systems for integration and control. Two principal methods are used: Chemical …
Amphibia. Frogs, Toads, Salamanders The common amphibians are the frogs, toads, and salamanders. They spend part or all of their existence in the water or damp places. Most lay their …
Human Blood Glucose Control ▶Blood glucose norm Blood glucose control is part of the energy management of the body and is a key homeostatic process. The normal blood glucose load …
Feeding patterns Macrophagous feeders (eat large food particles) include carnivores which eat meat (includes fish-eating piscivores, and insect-eating insectivores, etc.), herbivores which eat vegetation and omnivores which eat a mixed …
Chemical composition of protoplasm When protoplasm is studied chemically, it is found to be built up of the same elements that occur in nonliving materials. The 20 elements listed below …
Protoplasm The cessation of visible activities is due to the cessation of activities within the substance of the body. This living substance’ is known as protoplasm. As long as protoplasm …
Heart structure The heart is a muscular pump whose walls are largely made up of cardiac muscle anchored in a fibrous cardioskeleton. Blood returning from body tissues enters the right …
Functions of Blood Except in very small animals (e.g. flatworms) or those with very low metabolic rates (e.g. jellyfishes), simple diffusion from the surface of the body cannot distribute gases …
Pressure at high Altitude At sea level, there is approximately 0.2 atmospheres (20 kPa) of pressure driving oxygen from the atmosphere to the mitochondria where it is metabolized; above 8000 …