Sudoriferous and Sebaceous glands in Mammals:
Sudoriferous glands: Sudor = sweat. They are also called sweat glands and are distributed over most of the human body surface. These glands secrete sweat by a process called perspiration. Perspiration helps to regulate body temperature and maintain homeostasis, largely by the cooling effect of evaporation. In some mammals curtain sweat glands also produce pheromones (it is a chemical that an animal secretes and that communicates with other members of the same species to elicit certain behavioural responses).
Sebaceous glands: They are oil glands. They are simple glands connected to hair follicles in the dermis. They lubricate and protect by secreting sebum. Sebum is a permeability barrier, an emollient (skin softening agent) and a protective agent against micro organisms. Sebum can also act as pheromone.
Hydrostatic skeleton:
Skeleton of invertebrates is a core of liquid (water or a body fluid such as blood) surrounded by a tension resistant sheath of longitudinal or circular muscles. It is similar to water filled balloon because the force exerted against incompressible fluid in one region can be transmitted to their regions. Contracting muscles push against hydrostatic skeleton and the transmitted force generates body movements as the movement of sea anemone. Lumbricus (earth worm) contracts its longitudinal and circular muscles alternately creating a rhythm that moves the earthworm through the soil. In both the hydrostatic skeleton keeps the body from collapsing when its muscles contract. Invertebrate hydrostatic skeleton can take many forms and shapes such as gastrovascular cavity of acoelomates, a rhynchocoel in nemertines, a pseudocoelom in aschelminthes, a coelom in annelids or a hemocoel in molluscs.
Amoeboid movement:
Plasma membrane of amoeba has adhesive properties since new pseudopodia attach to the substrate as they form the plasma membrane. A thin fluid between plasma membrane and ectoplasm facilitate this sliding. As amoeba moves, the fluid endoplasm flows forward into the fountain zone of advancing pseudopodium. As it reaches the tip of a pseudopodium, endoplasm changes into ectoplasm. At the same time, ectoplasm near the opposite end in the recruitment zone changes into endoplasm and begins flowing forward.
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