7th Grade Science Student ebook

15.3 VERTEBRATE STRUCTURE AND FUNCTION

CHAPTER 15: ANIMALS

Internal skeleton All vertebrates have an internal skeleton. The skeleton provides

support, protection, and a place for muscles to be attached.

The skeleton of all vertebrate embryos is made of cartilage. In most

vertebrates, cartilage is replaced by bone as the organism grows

and develops.

Bones and

muscles work

together

The bones and muscles of vertebrates work together to

provide a structural framework for movement. Muscles are

attached to bones by tendons. A tendon is band of tough, fibrous

tissue that connects a muscle to part of a bone. Nerve signals cause

muscle groups to contract (shorten) and relax which, in turn,

causes bones to move.

Body cavity All vertebrates have a body cavity that holds the organ

systems. The body cavity of vertebrates has two regions

(Figure 15.19). The thoracic cavity holds the heart and the lungs of

air-breathing vertebrates. The abdominal cavity holds the digestive

organs including the stomach, intestines, and liver.

Organ systems Vertebrates have well-developed organ systems. The major

organ systems are summarized in Table 15.1.

Table 15.1: Vertebrate organ systems, their functions, and major organs.

Organ system Main function Major organs

Integumentary Barrier to external environment Skin, scales, feathers, fur

Skeletal Support and movement Bones, cartilage

Muscular Movement Muscles, tendons

Digestive Take in and digest food Stomach, intestines, liver, pancreas

Respiratory Exchange of oxygen and carbon dioxide Lungs or gills

Circulatory Transport materials to cells Heart, blood vessels

Reproductive Produce offspring Testes, ovaries

Nervous Response and movement Brain, nerves

Urinary Clean wastes from the blood Kidneys

Endocrine Regulate body functions Glands that produce hormones

Figure 15.19: The body cavity of a

vertebrate.