BIOD 151Pages1.1: Overview of Physiology and Major Systems of the Body!1.1: Overview of Physiology and Major Systems of the BodyAnatomy and physiology are studies of how the human body works. Anatomy focuses on the structure of the body and how it is designed, andphysiology looks at how the body func!ons. The physiology of the body depends on the anatomy of the body. The physiology of how the organsfunc!on depends on the structure of the bones, which are hard structures made of mineral deposits that protect the organs from damage. It isimportant to study anatomy and physiology together because they are so closely related.The human body has many levels of organiza!on(Figure 1.1). Studying the human body at thechemical levelis to look at atoms, which are the smallestbuilding blocks of ma"er. Atoms combine to form molecules, which then combine to form macromolecules (such as proteins and nucleic acids).Macromolecules combine to form organelles (working structures) inside of each human cell. Examples of organelles are the nucleus and mitochondria ofthe cell. The cells are the smallest units of living organisms and comprise thecellular levelof structural organiza!on. There are many different types ofcells in the body that perform various func!ons; together, they form the!ssue level.Figure 1.1Figure 1.1 Levels of organiza!on in the human bodyTissuesare groups of cells that perform a common func!on. The four basic!ssue types in the human body are epithelium, muscle, connec!ve, andnervous!ssue, each of which is made up of specific cell types that perform specific func!ons.Epithelial!ssue(Figure 1.2) covers the body surface and lines the cavi!es of the body. The cells that make up epithelial!ssue are specialized for taskssuch as secre!on and absorp!on. The structure of epithelial!ssue contains closely packed cells with very li"le matrix (layer outside the cells). Epithelial!ssue can be found as one layer or in many layers. These cells are under constant cell division to replace dead cells that shed away.Figure 1.2Figure 1.2 Epithelial!ssue lining the cavi!es inside the body shown in pinkMuscle!ssue enables us to move (Figure 1.3). The cells that make up muscle!ssue are specialized for muscle contrac!on.Figure 1.3Figure 1.3 Anterior view mul!ple layers of muscular!ssue (visible in context with skeleton, internal organs, arteries, and veins)Connec!ve!ssue(Figure 1.4) offers support and protec!on of body organs and includes bones, tendons, blood, and ligaments. Connec!ve!ssue cellsare specialized to bind!