{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

endocrinesystem

endocrinesystem - Animal Hormones Hormones and Their...

Info icon This preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Animal Hormones
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Hormones and Their Actions Hormone-secreting cells are called endocrine cells . Cells receiving the hormonal message are called target cells and must have appropriate receptors. The binding of the receptor activates a response. The distance over which the signal operates distinguishes hormone groups; some act close to the release site, others at distant body locations.
Image of page 2
Hormones and Their Actions Hormones can be classified into three main groups: Peptides or proteins. They are water soluble and transported by vesicles out of the cell that made them. Steroid hormones are lipid-soluble and can diffuse out of the cell that made them but in the blood they must be bound to carrier proteins. Amine hormones are derivatives of the amino acid tyrosine. Some are water- soluble and some are lipid-soluble.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Hormones and Their Actions The receptors for lipid-soluble hormones are inside cells, either in the cytoplasm or in the nucleus. The action of lipid-soluble hormones is mediated by intracellular hormone receptors that usually alter gene expression.
Image of page 4
Figure 42.1 Chemical Signaling Systems
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Hormones and Their Actions The epinephrine acts on different cells in the body: In the heart, it stimulates faster and stronger heartbeat. Blood vessels in some areas constrict to send more blood to muscles. In the liver, glycogen is broken down to glucose to provide quick energy. In fat tissue, fats are mobilized as another energy source.
Image of page 6
Hormones and Their Actions Growth factors , which stimulate growth and differentiation of cells, are a major class of paracrine hormones. Growth factors also act as autocrine hormones: Some of the hormone influences the cell that secreted it, preventing the cell from secreting too much hormone. Neurons may also be considered to be paracrine cells because they use chemicals called neurotransmitters to send
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Figure 42.2 The Endocrine System of Humans
Image of page 8
Vertebrate Endocrine Systems The pituitary gland of mammals is a link between the nervous system and many endocrine glands and plays a crucial role in the endocrine system. The pituitary gland sits in a depression at the bottom of the skull and is attached to the hypothalamus. The pituitary is made of two parts: anterior and posterior.
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Vertebrate Endocrine Systems The posterior pituitary releases two hormones: antidiuretic hormone and oxytocin.
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern